system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do SSDs have limited amount of rewrites?

Why do SSDs have a limit rewrites whereas from what I recall, HDs didn't have this concern? (though they broke often haha) SSD's have no moving parts, so I'm curious, is it just the current that damages it over time? What happens exactly?
gpt
HDDs work by rearranging some particles using a magnet. You can do that more or less infinite times (at least reasonably more than what it takes for the mechanical parts to wear down to nothing).

SSDs work by forcibly injecting and sucking out electrons into a tiny, otherwise insulating box where they stay, their presence or absence representing the state of that memory cell. The level of excess electrons in the box controls the ability of current to flow through an associated wire.
The sucking out part is not 100% effective and a few electrons stay in. Constant rewrite cycles also gradually damage the insulator that electrons get smushed through, so it can't quite hold onto the charge when it's filled. This combines to make the difference between empty and full states harder and harder to discern as time goes by.