Is standard procedure to just drink Mutation every time? I got 5 before D14, drank 2 already.
With 3 remaining, I can't help but wonder what other great abilities I might develop... I struggled a bit going down, occasionally got pretty close to death, so I'm not sure how much I can risk as this point.
So that's a no IMHO. I like to hold onto pots of Mutation because once you reach deep enough areas, you are pretty much guaranteed to get negative mutations.
Some mutations you can live with, but mutations like teleportitus, degrading stats on damage, losing the ability to read scrolls or drink potions on damage, even yelling loudly all the time can cut short a promising run.
At that point you absolutely will need your potions to cure them.
I've definitely lost games because the dungeon didn't give me enough pots of mutation to recover from all the mutations I received.