Rapture cooldown tracking and you!
Most of you have read on guides about the http://wotlk.openwow.com/spell=47537 trick, where you spam your shields to the whole raid before a big AoE ability in hopes to benefit by as many procs as possible when the internal cooldown of the talent is up, gaining back mana for ALL http://wotlk.openwow.com/spell=48066 that were active and were fully absorbed when the damage occured.
It's a crucial ability for discipline priests, because it is the main source of our mana regen. Tracking the cooldown of the talent can be hard if you do it manually you basically have to guess, so If you love your mana points you might want to consider downloading the addon called Ingela's Rapture
You can see how it looks in-game here, you can customize it by changing the width, height and color of the bar to what suits you best.
I hope this helps someone, enjoy!