Take for instance, the spell Prayer of Healing (in the online Basic Rules):
Up to six creatures of your choice that you can see within range each regain hit points equal to 2d8 + your spellcasting ability modifier. This spell has no effect on undead or constructs.
The "Damage Rolls" rule says that "If a spell or other effect deals damage to more than one target at the same time, roll the damage once for all of them." Does that same principle apply to "Healing Rolls"?
That is, if I target my whole party with a spell like this, is it a separate 2d8+modifier that gets rolled independently for each target, or do I just roll the once and that same amount is what each target gains?
Obviously the game "works" either way, and playing it however one's table finds most fun is great. But, I'm looking for official sources or references if available. If there aren't any, then I would accept any semi-official or well-informed well-reasoned arguments, preferably backed up by evidence that it's the usual way that groups handle this.