Since Social Security won't provide enough income to cover the bills in retirement, it's on us as individuals to save independently so we're able to live comfortably during our golden years. Unfortunately, only 38% of younger workers seem to have gotten that particular memo, because the bulk of millennials have not yet begun building a nest egg.

That's the latest from a TD Ameritrade study, which also unearthed some even more disturbing news: The average age at which millennials plan to start saving for retirement is 36 -- over a decade after college graduation for many who got degrees right out of high school. By waiting that long, countless younger workers will lose out on years of compounded returns, thereby putting themselves at risk of not accumulating enough money to retire. And the sooner they realize that, the sooner they can expedite their savings efforts and set themselves up for a financially sound future.

Group of young adults posing and smiling for a group photo

IMAGE SOURCE: GETTY IMAGES.

What will delaying your savings efforts cost you?

It's easy enough to make excuses as to why you're not saving for retirement as soon as your career kicks off. Maybe you're saddled with student debt. Maybe your salary is not much to write home about. And maybe your living costs continue to mount, despite your best efforts to keep them more manageable.

Here's the thing though: Nobody said saving for retirement would be convenient or easy. But if you don't do it early on, you'll risk coming up short when you're older. Either that, or you'll have to make serious lifestyle sacrifices later on in your career to catch up.

Now the one thing you ought to do before starting to build your nest egg is establish your emergency fund. This is the cash you'll tap when unplanned bills come your way, and ideally, it should be enough to cover at least three months' worth of living expenses. But once you have that safety net in place, your next focus should be retirement. And the sooner you begin saving for it, the more growth your money will achieve, and the less money you'll need to part with each month to accumulate an impressive sum over time.

Check out the following table, which shows what your nest egg might grow to depending on your total savings window:

If You Start Setting Aside $200 a Month at Age:

Here's What You'll Have by Age 67 (Assumes a 7% Average Annual Return):

22

$686,000

26

$515,000

30

$385,000

36

$245,000

TABLE AND CALCULATIONS BY AUTHOR.

Now based on the above, you might argue that kick-starting your savings efforts at 36 puts you in a pretty good place as far as retirement goes. After all, $245,000 is a decent sum to amass.

But notice the difference between starting to save at 36 versus doing so 10 years earlier. If you give yourself a 41-year savings window, which would mean first starting to build your nest egg at 26, and set aside $200 a month during that period, you'll be looking at a $417,000 gain if your investments manage to generate a 7% average annual return during that time, which is more than doable if you load up on stocks. Wait 10 years, however, and you'll be looking at a $170,000 gain -- again, still impressive, but not quite the same ring as $417,000.

Also, to give you a sense of what that difference might mean in retirement, imagine you decide to withdraw from your savings at a rate of 4% each year. If you wind up with $515,000 to work with, that will give you $20,600 of income. But if you wait 10 years to start saving and only end up with $245,000, you'll be looking at $9,800 of income per year instead. And that could spell the difference between enjoying retirement and suffering financially throughout it.

One major benefit of being young is having a great opportunity to accumulate substantial wealth for the future. So don't blow it. Remember, the figures above assume a $200 monthly savings contribution, but if you start saving in your 20s and are able to increase that figure, you could end up retiring a millionaire many times over. While your golden years might seem like the sort of the thing you don't need to worry about at present, remember that for each year that goes by without adding money to your nest egg, you increase your risk of coming up short when you're older and far more financially vulnerable.

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