As thm i use A LOT of spells: cures, buff, paralyze,slow, poison, dia, bio, scourge+banish for the debuffs, shadowsear, chainspell when i'll exp conjurer too <_< absorsb + initiate if i have time.
People spamming random spells are just taking their job lightly.

Ps: i'm speaking of mobs with a proper duration, like NM or even regular grinnding mobs. Leves don't count if you play under 3 stars.