How often should I change the thermal paste on my GPU?

Never! I've had PCs that are over a decade old on the original thermal paste, and they still perform just fine. Unless your GPU starts overheating, there's really no need to mess with it.

With decent quality paste, it's probably just going to last until you decide to upgrade your GPU. In my experience, I’ve never had to replace thermal paste unless things went south.

You really shouldn't need to change it unless you're having thermal issues. Good thermal paste can last for many years, so unless you see higher temps that aren't due to dirt or other factors, don't worry about it too much.

Honestly, I’d say you might need to change it every 8 years or so! It’s really not something you’ll need to maintain regularly unless you're seeing some serious thermal issues.

It’s usually unnecessary unless you notice rising temperatures. If your GPU runs hotter over time without any explanation, then it might be time to consider reapplying. But in normal use, it should last quite a while.