Workers today are advised to save for retirement, but many don't listen -- or, they want to heed that advice, but they wind up struggling to set funds aside for the future. In fact, 45% of Americans have no money earmarked for retirement at present, according to GOBankingRates.

Now saving for retirement may seem like a pain -- or even an impossibility. But if you don't make that effort, you're highly likely to regret it. Here's why.

Senior man holding eyeglasses

IMAGE SOURCE: GETTY IMAGES.

1. Social Security won't pay you enough to live on

You might think you'll manage to pay all of your bills once your Social Security benefits start rolling in. But actually, those benefits are only designed to replace about 40% of the paycheck you're used to from work, and most seniors need roughly twice that amount to maintain a decent standard of living. As such, you'll risk struggling financially if you don't enter your golden years with savings of your own.

Still not convinced? Consider this: Social Security pays the average recipient today about $18,000 a year. If that's not enough for you to live on, then you'll definitely need to ramp up on the savings front.

2. Inflation means Social Security will be even less helpful

Not only is Social Security not designed to replace your workplace earnings in full, but it also does a poor job of keeping up with inflation. It's estimated that seniors on Social Security have lost a whopping 33% of their buying power since 2000, largely due to the fact that the program's cost-of-living adjustments have been minimal over the past 10 years. As such, you'll need savings of your own if you want a shot at keeping pace with rising living costs.

3. Your healthcare bills may be higher than expected

It's no secret that healthcare is a major expense for seniors. But you may be surprised to learn that the average healthy 65-year-old couple today is expected to spend an alarming $387,644 on medical care throughout retirement, according to cost projection software provider HealthView Services. If you want to avoid financial struggles due to high medical bills, you'll need savings of your own.

4. You may not be able to work in retirement

Some people assume that if they don't save for retirement, they'll just pick up some part-time work once their main careers close out. But while working in some capacity is a great idea in theory, it may not pan out in practice. If health or mobility issues strike early on in retirement, getting to and from a job -- and holding one down -- may not be feasible. And if you live in an area where local jobs aren't easy to snag, you might struggle to find work. And let's not forget the fact that after a lifetime of plugging away, you may realize that you just plain don't want to work in retirement. But if you don't have savings, that lack of a job becomes all the more problematic.

Save for retirement while you can

Socking away money for your seniors years isn't easy -- but with some modest sacrifice, you can pull it off. Comb through your budget and identify some expenses to cut back on. If you're able to free up $250 a month over a 25-year period, and you invest that money at an average annual 7% return (which is doable with stock investments), you'll end up with about $190,000. Make it $350 a month, and you'll have $265,000.

Of course, the more money you're able to set aside for retirement, the better. But at the very least, make sure you're able to end your career with some amount of savings. Otherwise, you're likely to find that your senior years are nothing more than one extended financial struggle.