FF's are notoriously easy - meaning, if it's for anything else but a major boss or side-quest, taking the time to level grind is going to make the game mind-numbingly easy. This then leads to a level of boredom as the game becomes uneventful, monotaneous, etc...

Just go with the flow. If you happen to be having a little trouble with a boss or other major event in the game - and you have taken the time to employ various tactics - then, and only then, level grind for a bit.

This game is slaughtered by over-leveling, and it's not difficult to do in this FF, so be careful.