Just as your investments are subject to various risk factors like rising interest rates, currency risk, and economic turmoil, there’s another type of risk you may not have even considered: your own mental well-being.

When you think of the term “cognitive decline,” the most extreme cases likely come to mind—dementia or Alzheimer’s. But the reality is, as you age, it’s inevitable that you’ll experience at least a small level of cognitive decline. Around 20% of people in their mid- to late-70s experience mild impairment, and that percentage grows to half of all people in their 80s.

Even if you’ve successfully built a sizable nest egg during your working years, developing and implementing a withdrawal strategy in retirement can often be the greater challenge. Trying to go it alone, even with full cognitive ability, is often a risky way to repay yourself for all those decades of diligent saving.

Here are a few reasons why the decumulation phase is challenging for retirees, and what to do to prepare yourself for future mental impairment.