Originally Posted by
Ridcully
Dot durations are periodic:
Agony reaches minimum duration (>23s) at 1762, jumps to max duration (<25s) at 1763 and then it repeats for each 3525 haste rating.
Corruption reaches minimum duration (>17s) at 2349, jumps to max duration (<19s) at 2350 and then it repeats for each 4700 haste rating.
Agony reaches minimum duration (>13s) at 3021, jumps to max duration (<15s) at 3022 and then it repeats for each 6043 haste rating.
Dot duration can significantly change it's dps, ua being the best example: damage/15 is much lower than damage/13, about 13% less dps. Due to nature of dots, it can be worth to use decreased dot durations, over the duration of the fight you will only lose 2-3 gcd's. Also it seems to be self-balancing system and it is safe to ignore durations.