This story is part of CNBC Make It's Millennial Money series, which profiles people across the U.S. and details how they earn, spend and give away their money. San Francisco residents Rachel Shinto and Scott Johnston, both 28, may live in the most expensive city in the U.S., but they're still able to save money, invest for the future and enjoy their lives. "I literally feel energy when I come into the city," Shinto says. "I think it's a magical place where you can make anything happen if you want to." The couple, who got engaged earlier this year, share a one-bedroom apartment in Diamond Heights, a San Francisco neighborhood, and earn a combined $200,000 per year. Despite the Bay Area's high cost of living, the couple agrees that they're able to live well on their joint income. After earning just $300 per month while working in the Peace Corps, Shinto says dealing with San Francisco prices is easy: "I'm living my dream life right now." Johnston acknowledges that they're lucky to earn as much as they do. "We've never had to worry, but we do make a fairly comfortable salary," he says. Because Johnston earns more, he pays more in rent and covers the utilities, but the couple typically split expenses evenly. "I don't think we've ever fought about money yet," Johnston says. "There's nothing to hide — we're open about it."

Scott Johnston and Rachel Shinto go for a walk in the Mission District in San Francisco. CNBC Make It

The couple plan to get married in 2020 and pay for the wedding using their savings. They're budgeting around $40,000 for the event. Long-term, Johnston hopes to be financially independent by 40 and start a real estate company with friends. Shinto would like to continue working until she's 62 so that she'll receive her full retirement benefits. But she doesn't mind: "I love my job and I believe in public service." Despite their differing retirement aspirations, they're still partners in their finances. "Now that we're engaged, my money is her money, the way I see it," Johnston says. "We're going towards the same goal."

What they earn

Shinto earns $75,000 a year as an immigration officer for the Department of Homeland Security and U.S. Citizenship and Immigration Services. Johnston brings home $130,000 as an assistant controller and CPA for WalkMe, a start-up in San Francisco. In his position, he helps manage the company's finances. Johnston has changed jobs several times in the past few years, boosting his salary with each move. He started his career as an accountant earning around $50,000 per year, but after three years he decided to try something different. "I became an assistant controller, and I was making $75,000," he says. "Then I moved jobs again, and I was making $90,000." Shinto's career took a different path: Before working for the government, she served in the Peace Corps from 2014 to 2016. "I was an agriculture extension agent in Panama, and I lived and worked in a subsistence farming community with farmers who mainly grew subsistence crops," she says.

I literally feel energy when I come into the city. I think it's a magical place where you can make anything happen if you want to. Rachel Shinto

While there, she earned just $300 per month, which forced her to get by on a shoestring budget. She paid $30 a month for a house without running water or electricity and ate as cheaply as possible. "I really only had enough money to buy food and to travel out of my community to get more food. That's where I really learned how to pinch pennies and live off lentils and beans and rice," she says. Now that she lives in San Francisco, a city known for its outrageous cost of living, Shinto says she draws on her experience in Panama to put things into perspective. Before the Peace Corps, "I believed in retail therapy," she says. But during her time abroad, she couldn't afford to shop in the same way as she had in the past. "I wouldn't be able to eat if I did that." "Now I believe in spending money on experiences and investments in myself, like doing yoga teacher training and fitness classes that will benefit me in my health," she says.

What they spend

Here's a breakdown of everything Shinto and Johnson spend in a typical month. All numbers are rounded to the nearest ten dollar amount for clarity.

Housing: $2,640

The couple split a one-bedroom apartment for $2,590 per month. Shinto puts $1,200 toward rent and Johnston pays $1,440. Johnston also pays $50 per month for a parking spot in the building's garage, where he's able to charge his hybrid car for free. "I used to pay $275 for parking, so $50 is a good deal," Johnston says.

Debt repayment: $680

Shinto pays around $300 per month toward the student loans she took out for her undergraduate degree. She started with around $24,000 total and has about $13,000 left to go. As a government employee, Shinto is eligible to take advantage of the Public Service Loan Forgiveness program, but it doesn't make sense for her situation. The program stipulates that candidates can have their loans forgiven after making minimum payments for 10 years. Shinto will have paid off her loans in full before she hits the 10-year mark, so she decided to pay them more aggressively now. "That government program is really for people who have more than $30,000 in loans," she explains. "It wouldn't have been beneficial for me."

Rachel Shinto and Scott Johnston working at their home in San Francisco. CNBC Make It

Shinto's mom also contributes when she can. "My mom had been helping me for the past year, contributing $250 a month," she says. When her mom isn't able to help, Shinto increases her own monthly payments, up to $500 per month. She hopes to pay them off completely within the next two years. Johnston doesn't have any student loans, but he puts $375 per month toward his car loan. He purchased the car in 2017 and has about $14,000 left on the $19,200 total.

Food and drinks: $650

Shinto and Johnston go grocery shopping once a week and spend around $60 per trip. Including a few additional random stops throughout the month, they spend between $240 and $260 on groceries each month, which they split evenly. The pair also spends another $400 per month on dining out, grabbing drinks and treating friends and family when they travel. They split these expenses evenly as well. The exact amount fluctuates depending on how busy they are: "Some months we go out more, some we go out less," Shinto says. In general, "we try to not spend too much on going out."

Miscellaneous: $440

The couple travels on a regular basis and estimate that they spend between $2,000 and $3,000 per year, which they split evenly. That averages out to around $200 per month. In addition to weekend trips to visit friends and family in California, they also take about four longer vacations per year. The pair spends around $40 per month to do laundry in their apartment building. "We do a lot of laundry because we go through a lot of clothes with working out," Shinto says. Shinto allocates $100 for various beauty expenses, including manicures, blowouts and eyelash extensions. "I try to do it only for special occasions," she says, such as when she was a bridesmaid in a recent wedding. "It's something I've really tried to cut down my spending on." Shinto and Johnston also budget about $50 each for random spending throughout the month: anything from movie tickets and golfing to trips to the drugstore.

Subscriptions: $230

Shinto pays $15 per month for a shared Spotify account. They borrow login info for Netflix, Hulu, HBO and Amazon Prime from friends and family. "We're still mooching," they joke.

Scott Johnston and Rachel Shinto share a beer. CNBC Make It

Johnston's gym costs $50 a year, which comes out to around $5 per month. Shinto uses the free gym at her work, but also pays around $170 a month for boutique fitness classes. Shinto works part-time at CorePower Yoga and spends all of her earnings on a monthly plan, so she ends up only paying around $40 a month for an unlimited membership that would otherwise cost around $200. Additionally, she's training to be a yoga instructor at CorePower. Once she completes her certification, she'll start working there four hours per week earning $16 per hour. She'll also be able to take free classes at CorePower's affiliates, which include SoulCycle and Barry's Bootcamp, saving her even more.

Insurance: $220

Shinto's health insurance costs $120 per month and dental costs another $25. Johnston's health insurance is covered completely by his employer. He pays around $65 per month for car insurance and $5 per month for renters insurance. He also has an annual engagement ring insurance policy that costs $98 per year, averaging out to around $5 per month.

Transportation: $190

Shinto's job pays for her MUNI pass and BART tickets within the city. Occasionally, she'll take ride-sharing services, such as Lyft or Uber, if she's going out at night and wants to avoid public transportation for safety reasons. That costs around $80 per month. Johnston takes the BART to and from work, which costs him $4 per day and adds up to around $70 per month. Through work, he's able to load a card with pre-tax dollars to pay for public transportation, which saves him a small amount each month. He uses Lyft from time to time as well, but only spends around $20 a month. Johnston's car is a hybrid, so he's able to charge it in his apartment building's garage and drive around San Francisco on electricity. Because he only needs to fill the tank with gas for longer trips, he doesn't spend more than $20 per month on fuel.

Utilities and Wi-Fi: $180

Johnston covers all the utilities. He pays $60 per month for their Wi-Fi, and the building management lumps electricity, gas, water and trash into one bill that runs about $120 per month.

Rachel Shinto was given her dog, Boca, by a neighbor while serving in the Peace Corps in Panama. Boca now lives with the couple in San Francisco. CNBC Make It

Dog: $180

While Shinto was in the Peace Corps, her neighbors gifted her a puppy named Boca, which she brought back to California when she completed her contract. Boca lived with Shinto's parents for a few years, but when Shinto and Johnston moved into a pet-friendly apartment in January, Boca came to live with them. Each month, the couple pays $160 for a dog walker and around $20 for food, which they split evenly. They haven't needed to take her to the vet yet, but anticipate adding those expenses to their budget when they come up.

Phone: $0

Both Shinto and Johnston are on their family phone plans. "We're really lucky...both of our parents insist on paying our cell phone bills," Shinto says.

What they save

Over the past year, Shinto bumped up her contributions into her Thrift Savings Plan, a tax-advantaged retirement savings account offered to federal employees, from 3% to 5% of her annual salary, which comes to around $3,775 annually. She also puts $250 into a Wealthfront investment account each month. "Scott is the best at saving, and I am the spender," Shinto says. "But I have been saving since I got my job."

Scott Johnston and Rachel Shinto in San Francisco. CNBC Make It

Johnston puts 10% of his annual salary, or $13,000 a year, into his employer-sponsored 401(k) plan, which is half Roth, half traditional. That means some of the contributions are taxed right away, while others are added pre-tax. His employer doesn't offer a matching program, although he says he's working on getting the company to consider adding one. Johnston also aims to put around $1,500 per month into various investment accounts, primarily through Robinhood and Webull, as well as a small deposit in Acorns. The couple estimates that they're typically able to save another $2,300 per month, based on what's leftover from their paychecks after expenses, bringing their total savings and investments to around $5,500 total per month. The additional money is divided between investments and savings, and they try to keep around two months' worth of cash in checking, Johnston says.

I try not to put it into anything that's going to lose me money, especially if it's not even keeping up with inflation. Scott Johnston

The majority of the money they save goes straight into stocks and other investment vehicles, rather than traditional savings accounts. "I try not to put it into anything that's going to lose me money, especially if it's not even keeping up with inflation," Johnston says. "I put it into stocks — if I need it, I can sell a stock." Taking a cue from Johnston, Shinto does the same. "I used my Wealthfront account as a savings account," she says. "Because it's liquid, I can just take it out if I need it."

What the experts say

CNBC Make It asked Pamela Capalad, a certified financial planner and founder of Brunch & Budget, to comment on where Shinto and Johnston are doing well and how they could improve. Here are her thoughts.

Pamela Capalad, certified financial planner and founder of Brunch & Budget Source: Pamela Capalad

They should consider moving some savings into a traditional account

Overall, Shinto and Johnston are doing a great job putting money away for the future. "I love that they're saving a regular amount of money each month," Capalad says. However, their decision to put the majority of their savings into the market, rather than a traditional, FDIC-insured savings account, gives her pause. "When it comes to investing versus liquid savings, the point of liquid savings is not to beat inflation, the point of liquid savings is to keep your money in a safe place so it doesn't lose money," Capalad says. When your money is invested, if the market takes a dip, so do your savings. "At the end of 2018, for instance, people saw their portfolios go down by 20%," she says. "If they needed to access that money and needed to sell off some stock, what if they were selling their stock off at a loss?" In general, Capalad recommends investing for long-term goals, which she defines as anything more than five years out. However, investing is a personal choice. While she wouldn't tell Shinto and Johnston to pull all of their savings from the market, she recommends they keep at least three months' worth of living expenses in a savings account that won't fluctuate with market ups and downs. "Everyone has a different stomach for risk, and if Johnston's comfortable knowing that it could potentially be lost at some point if he had to take it out, then that's fine," she says. "But in general if you want to know that that money is going to be there for a certain amount of time, it makes more sense to put it into a liquid savings account at a bank that's FDIC-insured, where the balance is only going to go down if you spend the money."

Scott Johnston and Rachel Shinto plan to get married in 2020. CNBC Make It

And while stocks are somewhat liquid, there are still barriers to getting your money right away. "It's not a quick turnaround," Capalad says. "It's not just a matter of pulling out cash and using it, it's a matter of selling off the investments, waiting for everything to settle." If they needed it, "you can't access that money tomorrow," she explains. "It usually takes three days for stock sales to settle. Then you have to wait for it to transfer into your bank account."

It's a good idea to start estate planning

As Shinto and Johnston plan their upcoming wedding, it's crucial to begin estate planning as well, Capalad says. That includes listing each other as beneficiaries on any retirement accounts and adding each other as transfer-on-death to any non-joint accounts. That way, if anything happens to one of them, the other won't have to wait to obtain access to the money, Capalad explains. Additionally, they should start thinking about creating a will, naming healthcare proxies and giving each other power of attorney, especially if they're not planning to merge all of their accounts when they get married. These steps are relatively simple to accomplish and will eliminate any additional stress in the moment should something come up in the future.

Scott Johnston takes Boca for a walk. CNBC Make It

They should check out each other's insurance plans

Getting married is a great time for Shinto and Johnston to potentially upgrade their health insurance. If one of their employers offers a better insurance plan, it might make sense for them both to go onto the same one. It could be less expensive or offer superior benefits, Capalad says. Plus, "there's a special enrollment period when they get married where they can both unenroll or add somebody to their current insurance plans outside of the open enrollment period," she explains. "A lot of couples have found savings in that way when it comes to health insurance."

It's not too early to talk about how things will change when they get married