How often do you maintenance Water cooled PC’s?

I am not new to pc but i am new to building and maintenance my PC. I wanna take good care of it but i don’t know what tools i would need for it, plus i don’t want to fuck it up. But i feel if i take my pc into a shop for maintenance they will say something is wrong with it when it’s working 100% fine.

I know i can look at a video but that dosent explain what tools and any other tips i might need. Thanks, Advice would be much appreciated!