kill -15 $pid || kill -2 $pid || kill -1 $pid || kill -9 $pid

I could be wrong but I think beginners learn about -9 because beginners are more likely to start processes that they change their mind about and then cannot stop. Nothing wrong with this in the spirit of experimentation.

For more advanced users more familiar with the processes they start, I would guess -15 should be sufficient most of the time.