Ruin Explorer
Legend
Simple house rule. If a PC is Concentrating on something during a rest, they do not gain any of the normal benefits from that rest because they are too busy maintaining that Concentration. They can't rest and recover because they are too focused on that one thing. And if they do try, then Concentration checks are needed during the rest for them to split their focus between Concentration and recovery.
Why would you make this rule? Can you explain?
You'd be hurting players using a very small number of specific spells (I'm not sure it's even 10, I can check if you want), and as far as I can tell, just breaking RAW/RAI to slightly nerf them. None of these spells are particularly outrageous, and your house rule would be an extremely clear violation of RAI.
But perhaps you can point to some dreadful spell that is Concentration and lasts more than 1hr?