Changing jobs is exciting, but there are some practical things you'll have to deal with … like what to do with your old 401(k) plan. CNBC spoke with Nick Holeman, certified financial planner at Betterment, who broke down all of your options. 1. You can leave the money in your old 401(k) plan There may be a minimum balance required to leave your money with your old company, but most companies will let you do it. That said, there are a few downsides to keeping your 401(k) where it is, says Holeman: One, you can no longer contribute to it, and two, you'll have multiple 401(k) plans floating around. Plus, "if your old company gets bought or switches 401(k) providers, now you don't know your login information or your account number and it can be a pain to figure out." Leaving your funds with your previous employer is "definitely an option," he says, "but typically, the downsides mean it's not the best option."

2. You can roll over your 401(k) to your new employer's plan If your new employer accepts rollovers, "this is a good option if you like the investment choices and the fees aren't too high," Holeman tells CNBC. "This way, your money will all be in one account and it'll be easier to manage." If you aren't happy with the investment options offered by the new plan, or the fees are too high, you have a third option. 3. You can roll over your 401(k) to an individual retirement account (IRA) Your third option is to move your 401(k) into an IRA or Roth IRA, which is a great option because IRAs "typically have lower fees and more investment choices," Holeman explains. "They're both retirement accounts — you just get to pick when you pay the taxes," says Holeman of the difference between a traditional IRA and Roth IRA. With a traditional IRA, you contribute pretax dollars and let that money grow tax-deferred over time. You'll pay taxes on your contributions (and investment gains) only when you withdraw the money, which you can do starting at age 59½. If you withdraw before then, you'll have to pay a penalty fee. With a Roth IRA, contributions are taxed when they're made, so you can withdraw the contributions and earnings tax-free once you reach age 59½. There is an income cap on the Roth IRA: In 2017, only married people earning less than $186,000, or single people earning less than $118,000, are allowed to make the maximum yearly contribution of $5,500 (or $6,500 for people aged 50 or older).

"Once you know what your options are and what makes sense for you to do from an investment and fee perspective, then you actually have to execute the rollover," says Holeman. How to move your money You have two options when it comes to rolling over your money: a direct rollover or an indirect rollover. Holeman recommends doing a direct rollover: "When you do an indirect rollover, you're the one handling the money, so the 401(k) provider will write you a check and then it's up to you to actually deposit it into the new account. "There's just more that can go wrong, so I typically recommend doing a direct rollover and let the companies handle it." With a direct rollover, your 401(k) funds move straight to your new account and the money never passes through your hands. "You just have to fill out a form, sign it and the rest is pretty much out of your control," says Holeman.