It's a tricky balance, though. Having a ton of potions seems a bit silly, and too ARPG-ish, but if they're truly rare, and the combat is challenging, then you could easily end up in a terrible situation you can't really get out of. One solution is to have healing magic have a pretty long casting time. That way, your only real option for healing in combat is a potion - and they can be scarce to keep the difficulty up - but thanks to healing magic, you won't typically find yourself in the middle of nowhere with 1HP. It's just not so easy to use in combat.
