It's a situational awareness kind of thing. Are you and your team about to go into a situation with many enemies? Pop a buff/healing nade their way. Boss fight? Pop a nade and maybe a rift or Well of Radiance.
Also, use that melee ability. All buffs/heals speed up non-super regeneration, so you really don't need to be too picky with when you use those nades, melee, and rifts.
English
-
Soo it's more of a preengagment buff then a healing bomb as you say.
-
It can be both. I know it's hard to really tell how low on health your teammates are when you aren't mic'd up, but if you notice them taking heavy fire, and you have one charged, toss it their way. I've mostly been doing the preemptive buff though and saving my rift or Well for when it seems healing is most needed.