From the Player’s Handbook:
When a character tries to force a door open, roll a 1d20. If the result is equal to or less than the listed number, the door opens. A character can keep trying to open a door until it finally opens, but each attempt takes time (exactly how much is up to the DM) and makes a lot of noise . . . Numbers in parentheses are the chances (on 1d20) to open a locked, barred, or magically held door, but only one attempt per door can ever be made. If it fails, no further attempts by that character can succeed . . .Cook, 20
In other words, as a player you have two possibilities when it comes to opening a closed door: either it is (A) a door which the players can open or close with difficulty and which may be attempted infinitely; or (B) it is a locked, barred, or magically held door which only allows one attempt per character – ever. This is the first rule which I’ve run across in Advanced Dungeons & Dragons Second Edition (AD&D 2e) which I’ve had a hard time accepting.
Why does a locked door only allow for a single attempt? Has it somehow changed its internal makeup so that changes significantly from the last time an individual attempted to unlock it? Of course it hasn’t. Locks are picked all day, every day with thieves and locksmiths alike making more than one attempt on the lock.
What about barred doors? Why would they be a single attempt? Strongmen bend bars in competitions regularly and often do so after multiple attempts. Why then can’t a barred door have it’s bar bent as the strong character pulls successively on the door until the metal bends?
Logically there is no answer to these questions that doesn’t come back to, “because we said so,” in regard to the locked and barred doors. Unless someone has a significant reason as to why these should remain in the single attempt column I can see no reason why players shouldn’t be allowed to try these sorts of doors as long as they have interest in doing so.
On the other hand, I can totally understand that magically bound doors could be single attempts when it comes to physical interactions with them. It totally makes sense that a magical protection on a door could react to a physical interaction with it and adapt to the assault, similar to how an Artificial Intelligence (AI) is imagined to adapt to attacks in Science Fiction and Cyberpunk novels.
So unless someone comes up with a significant reason to keep this rule as it was written I’m adapting it to where only magically held doors are single attempt ever.
Cook, David “Zeb,” et al. Player’s Handbook for the AD&D Game. USA: TSR Inc, 1996. pg 20 PRINT