The average worker is deeply behind on saving for retirement, which is more troubling than some people might think.

If you're nearing retirement age and have little to nothing saved, you're going to be in for a rough retirement. Close to half (45%) of Americans don't have a penny saved for retirement, according to a survey from GOBankingRates, and three-quarters of survey participants say they have less than $50,000 stashed away.

The survey also asked workers why they weren't saving for retirement, and these were the three most common reasons.

Seesaw with a clock on one end and coins on the other.

Image source: Getty Images.

1. They don't think they make enough money to save

Roughly half of those who don't have any savings say they don't think they can afford to save. It's true that if the majority of your paycheck is going toward more immediate financial responsibilities -- like paying the mortgage or putting food on the table -- saving for retirement may not seem like a priority. But if you put off saving until the day you feel you can afford it, you may run out of time.

Saving for retirement takes decades, and if you hold off until you're just a few short years from leaving your job, you'll likely need to save thousands of dollars each month just to catch up. But when you start saving earlier and still have plenty of time before retirement, you may only need to save a few hundred dollars per month to reach your goal.

Of course, if you're struggling just to make ends meet, a few hundred dollars per month still may not be feasible. But it's better to save even a little than nothing at all. Even if you can only scrape together $50 per month, that will amount to nearly $57,000 over 30 years, assuming you're earning a 7% annual rate of return on your investments. That won't be nearly enough to retire comfortably, but it is a good start and certainly better than retiring with $0 in savings.

2. They have too many bills to pay

The second reason workers aren't saving for retirement is similar to the first reason. If you're living paycheck to paycheck and your top priority is paying all your bills, retirement may be the furthest thing from your mind.

However, you may have more cash to spare than you think. Although roughly 60% of Americans say they're living paycheck to paycheck, the average household spends close to $500 per month on unnecessary expenses, a survey from Charles Schwab found. So while you may have a long list of bills that are keeping you from saving for retirement, you may be able to trim some fat from your budget to start saving more.

Maintaining a budget is vital if you want to make sure all your money is going to the right places. Spend a month or two tracking all your expenses to see exactly how much you're spending and what you're spending on. Then divide up all your costs into different spending categories, like "essential," "nice to have," and "unnecessary."

Cut any of the unnecessary costs right off the bat. These could be anything from an unused gym membership to a TV subscription service you haven't used in months. Next, aim to cut back on the "nice to have" costs. You don't have to completely eliminate dining out or splurging on your morning coffee, but see if you can cut back those expenses to save even $5 or $10 per week. Every little bit counts, and making several minor budget tweaks can add up to hundreds of dollars per month.

If you're still strapped for cash, see if there are ways to lower your essential costs. That could mean making big decisions like downsizing your home to lower your mortgage payment, or it could be as simple as sealing the leaks in your doors and windows to save money on heating and cooling bills. Again, every little bit counts, and when you can lower your bills, it's easier to save more for retirement.

3. They don't think they need any retirement savings

The third-most-common reason workers aren't saving is perhaps the most surprising: They don't expect to need any savings in retirement. This could mean a couple of things. First, it could imply that workers aren't planning on retiring and expect to work for as long as possible. Or it might mean they're expecting to rely on Social Security benefits to get by in retirement. However, both of those explanations have their flaws.

Even if you're planning on working beyond the traditional retirement age, you'll likely still retire at some point when you become unable to continue working. Retirees are living longer than ever, with a third of today's 65-year-olds expected to make it to at least age 90, according to the Social Security Administration. You may be in excellent health now, but it's unrealistic to assume you'll be able to work into your 90s or beyond.

When you do eventually retire, you'll need savings. Social Security benefits will help cover some of your costs, but they're only designed to make up around 40% of your income. Unless you have a pension or some other source of retirement income, the other 60% will need to come from your savings. Especially considering the average retiree only receives around $17,652 per year from Social Security benefits, you likely won't be able to survive on your monthly checks alone.

Saving for retirement is challenging, especially if you don't have much cash to spare. When your biggest priority is simply making ends meet each month, retirement may seem like an impossible goal. Fortunately, with some simple lifestyle shifts and budget adjustments, you can (and should!) start saving more right now.