Potions are not useful unless you're a really low level.
The amount of hp/mp they restore, or the effects they have are too minute to make them worth buying/carrying much less use them in battle.
And then there's the recast times. I could maybe get by with restoring a measly 300mp if it didn't then take FOUR AND A HALF FREAKING MINUTES before I could use another one.
The only potion that is even halfway useful is Ironwill Ungeant, as it gives us the effect of Shell, which SE saw fit to deprive Conjurer of casting.
But even that has a cooldown of 10 minutes when the effect only lasts 5. So STILL no one ever uses it.
Potions should either have little to no 'recast' time, or give us boosts that are actually worthwhile.