What happens when you a change your job AFTER an approved I-140?

Hello!

I’m a year and a half away before my h1b expires, and while my employer is happy to sponsor my green card visa, I’m debating if it’s even worth it, given the backlog for Indians.

As of May 2024, it would take me 12 years to get my green card. Now, I know I can technically keep renewing my h1b until then (after getting an approved I-140), however, here’s my question: it’s obviously more likely that I will move jobs at-least once in the next 12 years. What would happen if I do that? My employer said I would have to do the PERM process all over again, what does that really mean? Has anyone else gone through this? Is it worth it to get an approved I-140 if the PERM process needs to happen again if jobs change? Could that mean that my new PERM could be denied even after getting accepted once?

Thank You