In most contracts under American law, you can sign away your rights forever and it’s just… no backsies. Like pretty much everything else in life. But not so much in copyright: in many situations, when you license or assign your work, you (eventually) have the right to terminate that transaction!
Those rights are called, unsurprisingly, "termination rights". And if your work is protected by copyright — so that’s you, photographers, musicians, writers, videographers — you should understand what these words mean to you.
Now, these rights generally don't kick in until 35 years after you assign or license the relevant work. 35 years is obviously a long time, but something like this situation has happened multiple times: a young photographer shoots a concert, a corporate event, or even a wedding for a client, and either licenses or assigns the rights to that work to the client. Fast forward several years, and someone in those pictures becomes famous... or infamous. Maybe the performer at the concert blew up, or maybe someone at that wedding ended up in the news for one reason or another. Guess what? That photographer eventually gets those rights back and therefore the photographer, not the client, can continue to get paid for that work 35 years after they assigned or licensed it.
Now there are some details you need to know to make sure that termination rights work in your favor. Like how and when to exercise them. And, honestly, you should try to structure your agreements with your clients so that you keep the rights to make money off your work even before those termination rights kick in. All of those are reasons to talk to a good attorney about your work.