I aim to level up my characters at least twice for every new area I enter. This keeps me ahead of the curve. Bravely default destroyed me for that.

There was a time in the later game during grinding I turned up the difficulty from normal to hard to see if the effects of changing difficult improved battle rewards (didn't seem to). I forgot to reverse this before a boss and despite being level 99 and taking things slowly and carefully the boss destroyed me. Hard mode too intense for me.