As someone who writes about saving for retirement all the time, it sort of pains me to admit that I did not, in fact, begin funding my nest egg the moment I found myself working on a full-time basis. Back then, in my early 20s, my priority was paying off my student loans and building up an emergency fund. I refused to put a dime into a retirement plan until I'd met those goals.

These days, I contribute to a retirement plan regularly. But I have a lot of friends who don't -- and the reason often boils down to mounting expenses.

As much as I might sound old saying it, it costs more money to function as an adult these days than it did when I was growing up. Nowadays, you need a cellphone, and cable or streaming services, and so forth.

A person at a laptop holding their head.

Image source: Getty Images.

So it's easy to see why only 41% of U.S. adults report that they currently have retirement savings, according to New York Life's latest Wealth Watch survey. For many, there just isn't money left over to save after paying those monthly bills.

But while I can sympathize with anyone who's struggling to build retirement savings, I can also say quite bluntly that retiring without a nest egg is seriously bad news. Your senior years might end up looking pretty bleak if you go in without a dime in savings.

You can't live on Social Security alone

Many people who don't manage to bring savings with them into retirement end up largely living on Social Security. But that can be very problematic.

Social Security, at present, will replace about 40% of your pre-retirement income if you earn an average wage. If benefits are cut, which is a distinct possibility in about a decade's time, your benefits will provide even less replacement income.

But even if that doesn't happen, if you retire without savings or another income source to fall back on, you're looking at taking a 60% pay cut. That's huge.

If you think you'll somehow manage, think about it this way: Could you cover your current expenses on just 40% of your pay today? If not, then chances are that it won't be doable in retirement, either. That's because a lot of your basic expenses are likely to stay the same.

You'll still need housing, transportation, food, and healthcare, for example, once you retire. Your housing costs might drop thanks to a paid-off mortgage, but that savings may be offset by higher healthcare expenses. So all told, a 60% pay cut in retirement generally doesn't make for a very comfortable lifestyle.

Try your best to save something

You may not be able to fork over hundreds of dollars each month for long-term savings, and that's understandable. But for the sake of your financial wellbeing in retirement, do try to save something.

Allocate $50 a month to your IRA or 401(k) for now and see if you're able to ramp up as your wages increase. Or start with $25 a month but bank windfalls, such as if you get a tax refund.

Saving for the future is really hard. There's no question about it. But if you don't make the effort, your senior self might end up seriously cash-strapped and overwhelmingly unhappy.