By the time you reach your mid-50s, there's a good chance you've thought about your own mortality. It appears that doesn't always translate into planning for the end of your life. Close to half of people age 55 and older (45 percent) don't have a will, according to a study released Thursday by Merrill Lynch and Age Wave. Just 18 percent have a will and two other key estate-planning documents: a living will and durable power of attorney (more on those below). That's despite a general consensus that people should have a plan in place by age 50. "People know this is something they need to do," said Kevin Hindman, national trust executive at Merrill Lynch. "They know they need to organize their affairs, put their estate plan together, and they think it's irresponsible if they don't."

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The study was based on a survey of 3,000 adults, focused on those age 55 and older, and explored attitudes and thoughts about end-of-life planning. While the topic might seem off-putting at first glance, 9 in 10 respondents said they are open to discussing their end-of-life preferences with family and friends. "I think this is healthy, and families need to embrace that and have these conversations," Hindman said. Of course, a will is only one part of estate planning. While estate planning might sound like something that only applies to wealthy people, that's not the case. An estate refers to what anyone might own: financial accounts, real estate and possessions.

Share of people age 55 or older with the essentials A will 55% Advance health-care directive or health-care proxy 41% A durable power of attorney 33% All three of the above 18%

Putting a plan in place for those assets helps ensure that upon your death, your wishes are carried out and that family squabbles don't evolve into destroyed relationships. In other words, it's partly about making things easier for your loved ones during an already difficult time. There also are parts of estate planning that have more to do with life than death. Here are the basic considerations.

Yes, you should have a will

If you have little in the way of assets, you might think you don't need one. Guess again. If you pass away without it — called "dying intestate" — the legal system in your state will decide who gets your assets, no matter how massive or meager. Worse, if you are the parent or guardian of a minor child and there's no will stating who you want to care for them, guess who appoints your replacement? A judge. And that's after family members have potentially given their 2 cents.

Choose an executor

When you create a will, you choose an executor. This is the person who will be in charge of carrying out your wishes. It can be a big job, so choose wisely. Things such as liquidating accounts, ensuring your assets go to the proper beneficiaries, paying any debts not discharged (i.e., taxes owed to the IRS), and even selling your home could be among the duties undertaken by the executor. "It can be a lot of work," Hindman said. "Think about the time it will take them and what they're required to do." In other words, just because you've known your best friend since elementary school doesn't mean handling the challenge of being an executor is up his alley. Same goes for a trustee, if you set up a trust.

Create an advance health-care directive

Also known as a living will, this document outlines your wishes if you become incapacitated due to illness or injury. "It's important to document your wishes about the type of care you want to receive under certain circumstances," Hindman said. Say you are on life support. Instead of a loved one making the agonizing decision whether to end all life-saving measures, your wishes would be specified in a legal record.

Assign powers of attorney

If you become incapacitated, the person you grant durable power of attorney will handle your financial affairs if you cannot. As with choosing an executor, make sure whoever you hand the financial reins to is trustworthy. That person will handle things such as paying bills, accessing your retirement accounts, or selling and buying investments. "You're giving power for them to have access to your assets and make decisions around your assets," Hindman said. More from Personal Finance:

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Check account beneficiaries

People often mistakenly think that in their will, they can name who gets the money in retirement accounts, life insurance policies and the like. Wrong. The person listed as the beneficiary on each of those accounts will get the money even if your will says otherwise. "Look at those beneficiary designations to make sure they're up to date," Hindman said. Also, when you have a major life event — say, a divorce — remember to revisit the beneficiaries on all your accounts.

Make a list of critical documents

While it can be hard to imagine your own death, picture your family having to search through drawers for your original will, documents regarding your bank accounts and other assets, and maybe even your Social Security number. The best way to avoid forcing them to deal with that task on top of mourning is to leave an organized list of information that the will's executor will need to settle your estate. Be sure this includes passwords so your online accounts can be accessed.

Follow up on your plan