warranty fine print—what should I watch out for?

- Good tip on clarifying "routine maintenance"... learned that one the hard way myself.
- Had a warranty claim denied once because I used aftermarket filters instead of OEM. Dealer said it was in the fine print, buried somewhere deep in the manual.
- Now I always double-check if using non-dealer parts voids anything. Usually it's okay, but some brands get picky about it.
- Curious if anyone's run into issues with DIY oil changes or tire rotations affecting warranty coverage? Seems like something they'd try to nitpick...