@Scyllan8 wizzard in my group wants to use the reduce spell on all locked doors to bypass them is this valid? I would ask the wizard which part of the door they're trying to reduce. Most doors are made of multiple objects.
— Jeremy Crawford (@JeremyECrawford) November 23, 2016
Perhaps use his Spell Attack modifier on a d20 roll to break down the door? Either he has the mastery required to make the magic work in that way, or he doesn’t.
You cant take every use people make if a spell and nerf it. A door is seperate frim the door frame and hindges, but yes the door .. An object is reduced. Be glad for your players happiness and be.glad he has one less spell slot.
Dictionary definition of door:
“a usually swinging or sliding barrier by which an entry is closed and opened also : a similar part of a piece of furniture”
As such the door is 1 object(assuming it isn’t multiple boards glued together or something similar) the knob, hinges etc are different objects on the door.
However to go with JC’s comment what if the player says the big wooden/metal thing the knobs and everything are attached to I reduce that, or in the case of for example a door composed of multiple boards connected he says the board the hinges are connected to I reduce.
I would allow this, simply because if a Caster really wants to waste a 2nd level spell slot (or 3rd, or 4th…) on something as mundane as a locked door, then go for it. Poor spell slot management.
I say that wizard is good to go, and clever. Conversely, according to JC’s reasoning, to enlarge a party member you would also have to choose either the physical person, and then a weapon, and then the bits and pieces of the armor and then each piece of equipment….etc.
Or you can treat reduce the same way most people use enlarge.
Except the spell specifically states that worn geae changes size with the creature:
“If the target is a creature, everything it is wearing and carrying changes size with it. Any item dropped by an affected creature returns to normal size at once.”
So even if Crawfords answer strikes as odd its consistent.
Make all your doors super magnetic. This causes the iron filings needed for the spell to fly out of his hands and be useless.
Let them do it, but the sound of screaming metal hinges, as they are ripped from the wall would likely make a LOT of noise.