Your 60s are the time to start really buckling down and planning for retirement. After all, there's a good chance that milestone is right around the corner. And if you manage to steer clear of these big mistakes, you'll avoid some of the financial stress so many seniors ultimately wind up with.

1. Not staying invested in stocks

You'll often hear that as retirement nears, it's a good idea to move away from riskier investments, like stocks, and instead load up on safer ones, like bonds. But that doesn't mean you should rid your portfolio of stocks completely. Quite the contrary -- you'll need stocks in your portfolio to keep generating investment growth for you during retirement, so don't unload all of them just yet. In fact, as a general rule, once you reach your 60s, you should still have about 50% of your assets in stocks.

Now there's wiggle room with that percentage depending on your specific age and personal appetite for risk. For example, if you're in your late 60s, you may feel more comfortable having more like 40% of your portfolio in stocks, and if you're in your mid-60s but have a higher risk tolerance, you may decide to keep 60% or 65% of your portfolio in stocks. The point, however, is that you shouldn't rush to get rid of stocks anytime soon.

Older man and woman at laptop with concerned expressions

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2. Not taking advantage of catch-up IRA or 401(k) contributions

Many seniors rely heavily on their personal savings to supplement their Social Security benefits, and chances are, you'll do the same. That's why it's a smart idea to make catch-up contributions in your retirement savings plan, especially if you're not all that happy with your present balance. If you have an IRA, you can make a $1,000 catch-up this year if you're in your 60s. With a 401(k), you get an even more generous catch-up: $6,500.

3. Not buying long-term care insurance

It currently costs over $90,000 a year, on average, to share a room in a nursing home, and close to $49,000 a year to reside in an assisted living facility. And these are just averages. If you've reached your 60s and haven't yet put any thought into long-term care, now's the time to get moving -- especially if you don't have children or other people in your life who could conceivably become caregivers should the need arise.

Though the best time to apply for long-term care insurance is during your 50s, it's not too late to do so in your 60s -- and the sooner you do, the better your chances of not only getting approved, but locking in an affordable premium. Having that insurance could spell the difference between affording the care you need with ease versus struggling yourself or putting an immense financial burden on your loved ones.

The moves you make during your 60s could set the stage for a financially sound retirement. If that milestone is coming up soon, be smart with your investments, boost your savings, and look into long-term care insurance. You'll be thankful you did.