Many people let their retirement savings fall by the wayside and instead rely heavily on Social Security to cover their senior living costs. But if that's your plan, you may be surprised to learn that Social Security doesn't pay as much as you might think it does.

Next year, seniors on Social Security are getting their largest raise in decades. But even in spite of that, the typical monthly benefit may not do a great job of helping recipients cover their expenses.

Social Security cards.

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What will seniors collect in 2022?

The average monthly Social Security benefit in 2022 will be $1,657. That's a big jump from the current average monthly benefit of $1,565. We can thank a 5.9% cost-of-living adjustment for that.

Now a monthly paycheck of $1,657 may be enough for some seniors to cover their bills. If you have a paid-off home and very few expenses, you might manage to just get by in the absence of other income.

But for the most part, $1,657 is not a lot of money to live on. And if you're not convinced, take a look at what you spend right now. Chances are, it's a lot more money. And while you may not have a mortgage payment to deal with once you retire, the rest of your living expenses could stay the same. Some, like healthcare, could even climb.

The point? It's important to have money outside of Social Security to help ensure that you have enough income to cover all of your needs.

How to save efficiently for retirement

Building a nest egg of your own to supplement your Social Security benefits could prevent you from encountering financial issues once you retire. In that regard, your best bet may be to save in a tax-advantaged retirement account like an IRA or 401(k) plan.

With a traditional IRA or 401(k), you get a tax break on your contributions. Then, your money gets to grow on a tax-deferred basis, and you pay taxes on the money you withdraw from your savings.

With a Roth IRA or 401(k), there's no up-front tax break on contributions. But investment gains in your retirement plan are tax-free, as are withdrawals.

How much savings you should aim for? A good rule of thumb is to expect to need 70% to 80% of your pre-retirement during your senior years. Social Security will replace about 40% of your former paycheck if you're an average earner, so your savings will need to provide the rest.

Now, say you sock away $300 a month in an IRA or 401(k) over a 30-year period. If your investments in that account deliver an average annual 7% return, you'll wind up with $340,000. That 7% is a bit below the stock market's average, so it's a reasonable assumption for a 30-year investment window.

Of course, the more money you're able to sock away for retirement, the better. But the key, either way, is to have access to savings so you're not reliant on Social Security alone.

While the average monthly benefit is rising in 2022, and may rise in future years, seniors who retire only on Social Security often find themselves cash-strapped. If you're rather not join their ranks, do your part to make sure you have additional income at your disposal.