Depends on their financial position overall. If you live below your means and save up, especially in a professional position, you can offset expenses with passive investment income. Retirement is really just getting to the point where passive income and using up savings can last you until you expect to die.

If you have passive income that covers your bills, then the main difference between working and not working (or doing work without guaranteed income) is that you're not getting ahead as quickly anymore. You're not necessarily even falling behind, though even that state could be maintained for a while depending on how much you have saved and what kind of credit you have access to.

But yeah, if you're living paycheck to paycheck, this isn't an option, you'll have to do the work around your other job.