Is using a timer required when submitting a run? Does this rule differ by game?

If you accidentally reset the timer during a run, is the run invalid?

No, a timer shouldn’t be required unless there are some weird circumstances that would need one (I can’t think of any).

And no, if you accidentally reset it, just continue on. You can retime the run after the fact.

Chances are you aren't going to be able to start and stop the timer in the exact frames needed anyway (some games have specific timing methods) and will need to look at the video to get your actual time.

I just find they're good for knowing your pace and see if your current run is good or not. And they look cool.

Im new to speedrunning but I like using a timer so I know if my current run is even worth completing or if I have wasted too much time to beat my best