Oh, yeah, I do that all the time. I enjoyed farming exp on those 3x Cactuar fights by putting Clear Minded on everyone while the Cactuars repeatedly tried to confuse me, and then I left it on through to the boss fight and that paid off when he had some kind of Propellor attack or something that spun everyone and then 'Guard' popped up on every character. xD Unintentionally being tactical, yes sir.

For the most part I keep Level Up, Ability Up on all characters, various different "_____ Killer", Counter and HP+ abilities on attackers and various status wards on my casters.