Spell Duration / ( Base Tick Time / ( 1 + Haste % in decimal form)) = Total Number of Ticks Rounding Up This is the basic formula for how haste works. I've been walking around the gym today putting some numbers together for the usefulness of Berserking and Heart of Ignacious. (this can also be used for mages with herbalism) Combustion has a 10 second duration and ticks once each second. Without plugging in numbers, for every 10% haste you have, Combustion will gain an extra tick. I have yet to see any modeling on SimCraft or Rawr as to how valuable these on use haste abilities can be, but I would wager they can be gargantuan in AoE situations. (You know, I've always liked that word... "gargantuan"... so rarely have an opportunity to use it in a sentence) Previously, and as a result of Combustion's previous form, I had been using Berserking to spam fireball and I believe this to be inefficient.