Saving for retirement takes decades, and it's important to check on your progress every so often to make sure you're still on track. If you reach retirement age and suddenly realize you can't afford to retire, there's not much you can do at that point.

By the time you reach age 50, you should be well on your way to achieving your retirement goals. And there are a few milestones to keep in mind that can help you head into your senior years better prepared.

Couple talking to a financial advisor.

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1. You should know how much you need to have saved

Once you've reached your 50s, you only have a decade or so left to save for retirement. So by this point, you should have a good idea about how much you need to save to retire comfortably.

If you don't know how much to save, now is a good time to calculate that goal. Even if you do have a target in mind, it's smart to recalculate your retirement number just to make sure your goals haven't changed. You might discover you need to save more than you previously thought, and finding that out now is better than realizing it right before you retire.

To determine your savings goal, start by running your information through a retirement calculator. Be sure you're accounting for Social Security benefits, a pension, or any other sources of retirement income as well because they can reduce the amount you have to save.

2. Think about how you'll pay for long-term care

Long-term care is one of the most costly retirement expenses you can face. The average stay in a nursing home costs nearly $7,000 per month for a semi-private room, according to the Department of Health and Human Services. Also, among those who require long-term care, the average person needs it for around three years. At a rate of $7,000 per month, that's a total of around $250,000 in long-term care expenses.

In addition, Medicare typically doesn't cover long-term care, so you'll likely be on your own to foot this massive bill. And because around 7 in 10 seniors will need long-term care eventually, according to the Department of Health and Human Services, it's wise to be prepared.

One way to help defray the costs of long-term care is to enroll in long-term care insurance. Although you likely won't need long-term care for several decades, signing up earlier in life will reduce your premiums. If you choose not to enroll in long-term care insurance, start thinking about how you'll cover long-term care costs. You may opt to save in a health savings account (HSA), for example, or simply set aside more cash in your retirement fund specifically for this expense.

3. Think about what age you'll begin claiming Social Security benefits

Nearly two-thirds (64%) of retirees say Social Security benefits are a major source of income, according to a survey from the Society of Actuaries. Because you'll likely be depending on your monthly checks for at least a portion of your income in retirement, it's important to choose wisely when deciding what age to begin claiming.

The earlier you file for benefits, the less you'll receive each month. You can begin claiming as early as age 62, but that will result in a permanent benefit reduction of up to 30%. If you delay benefits until age 70, on the other hand, you could receive your full benefit amount plus up to 24% extra each month. Claim at any age between 62 and 70, and your benefit amount will fall somewhere in between those two extremes.

Think about what age you plan to retire, then consider how that will affect your Social Security benefits. Keep in mind that you don't necessarily have to retire and claim benefits at the same time. For example, even if you're planning on retiring in your early 60s, you could still delay benefits and earn those bigger checks. Regardless of what age you decide to claim, make sure you know how it will affect your benefit amount.

Saving for retirement isn't easy, but setting goals for yourself can make it more likely you'll save as much as you need. By checking these three milestones off your list, you'll be on your way to a more financially secure retirement.