For nightstalker I use it to go invisible before my engagements, or if I'm trying to get away and I know I broke line of sight. For any other class it depends on the dodge. When I use marksman I focus more on straddling and hip firing, then when you stop to reload I dodge and then aim to finish you off. Or if I need to reload before a gun fight without losing a step, or lastly, I just use it to jump behind a wall in a gunfight to help me reposition or get out of there. With the gamblers dodge I mainly just use it to help me get away. Other than that I use it to next to weak enemies to keep my melee up and finish them off with my melee. If they aren't weak then I'll use it to recharge my melee then try to get away.

well since I use the dragons shadow I pretty much use it whenever i'm going into a fight since it gives me a movement speed buff for 10 seconds. Other than that I pretty much just use it on reaction. Like if i'm being pushed and i'm half way through my clip I dodge to reload and then either run or peek depending on the situation.

i use nightstalker and use gamblers dodge to turn myself invisible and flank people, they really dont expect it at all especially mid fight they think you retreat but your really on the back lines demolishing them, peoples awareness in the crucible is atrocious, when someone turns or is waiting and paying attention always a fun match. you can use it to simply roll off of a ledge quicker than anyone too to re-position. dont use it to save yourself use it to position, for instance, theres an open field and team fire i dodge to cover, continue running on as invisible 9/10 they dont see you and suddenly there all scrambling finding your fire stream then your team moves in and kills them.