What prevents a cleric from casting the Guidance spell every single turn and having everyone have 1D4 extra for their rolls, especially since you can combo it with this:
This can end with almost all the checks being a D20+1D4 plus advantage. Seems a bit broken mechanic without some houseruling that prevents the same spell on the same target for some time, or I am missing some rule that prevents this?
The same would affect Resistance, but since you probably are in the middle of a combat, the Touch range could prevent it effectively, but for normal skill rolls where the touch of the cleric is possible and the situation is not stressing?
Best Answer
Nothing prevents this in a normal, unpressed situation.
A lot of the same things that I said in my answer on the other question apply here as well.
Basically, if this is a strategy you don't want your PCs to employ, it's up to you as the DM to make the opportunity cost high enough that it's a significant trade.
There's not much issue with a cleric casting a 1 action cantrip while the thief picks a lock unless the thief needs to get through the room in order to hit a button to stop wave after wave of zombies. Then the Cleric is choosing between turning undead and helping the rogue.
Or perhaps there is a time pressure where there is something that has to be done within X rounds and casting guidance and then waiting a whole round for the rogue's turn to come back up isn't feasible.
Basically, this strategy is valid, until it's not. It's up to you to design situations that makes its use meaningful (though in the vast majority of cases, it's really kind of pointless to prevent this strategy).