Am I literally just wasting time if I'm not trying to raise skill points during their "boost" effects?
E.g. studying in the rain at night/diner.
I've studied at night several times, got all the classroom questions right and still level 1 Knowledge. Meanwhile, I went to the Bathhouse on a Monday night once and instantly hit level 2 Charm.
I think knowledge has a way higher threshold to raise a level than all the other stats because it's offset by all the opportunities for points you have (all the classroom quiz questions, for example). I don't have proof of this though.