There's a reason so many older Americans wind up working in some capacity: Money tends to get tight in retirement. And you might find that you need an income boost once your time in the workforce comes to an end.

Social Security is a major income source for a lot of seniors. But those benefits could be cut in a little over 10 years if lawmakers don't find ways to pump more money into the program.

Plus, your nest egg might not go as far as you expect it to. You could kick off retirement with $500,000 in an IRA or 401(k) plan, but if market conditions deteriorate, you could be down to $450,000 in savings within a year or two, forcing you to scale back on withdrawals.

But maybe money issues won't come to a head during retirement. Maybe you'll end up with plenty of savings, and market conditions will trend in your favor. And maybe Social Security benefits won't be cut -- or you'll have snagged such a large benefit that you can afford a hit.

If so, you may not need to work as a retiree. But here's why you may want to find a job anyway.

It's a matter of your health and happiness

For many people, work is more than just a paycheck. It's a means of staying mentally and physically active, and it's a way to engage with other people socially. That's why it could be worth it to seek out work in retirement even if money isn't tight at all.

A smiling person wearing an apron in a bakery.

Image source: Getty Images.

Many retirees struggle with feelings of boredom and isolation. Having a job to go to on a part-time basis could help address both issues. Plus, it could serve the very important purpose of getting you out of the house.

Wthout a job, you might start to lead a very sedentary lifestyle. That could be detrimental to your health. But if going to work means walking seven blocks each way to a bus stop and moving around during the day, as opposed to being planted on your couch, then it could help you stay in good shape and stave off health issues.

It's not just a matter of being able to pay the bills

It's fair to say that many people who work in retirement do so out of financial necessity. But even if you don't have money problems in retirement, you may want to consider working for the other benefits.

And if you really don't need the paycheck, you could give that money to a family member or donate it to charity, both of which will give you something to feel good about.

Lastly, if the idea of working isn't so appealing, and you don't have a need to boost your income, you could look at volunteering instead. Doing so might be a better choice since it won't put you at risk of ending up with a higher tax liability.