How do you know when you get a crit and it becomes free? Is there some kind of graphics representation? Surely you don't have to look down at that tiny buff bar and weed it out do you?
Pretty much. However, if you're using Rejuvenate beforehand it's pretty much guaranteed. On my Seer, I have about a 30% Force Crit chance unbuffed. Conveyance brings that up to 55%. The chance of not getting a crit is about 1 in 24.