There's a balance to strike. If the rules change constantly, or even just too often, you're not really playing a game anymore, you're in Eternal Beta Test, which suuuuuuucks as a player. If the rules are utterly inflexible and never adapt to anything ever for any reason, that too leads to problems.
Another way of saying this is that your "If needed" is doing some incredibly heavy lifting there. If that happened more than, say, once every several months (of weekly sessions), I'd get pretty annoyed as a player that the rules weren't being consistently applied. If it happened quite regularly, e.g. multiple times a month for weekly sessions, I would be looking for a chance to have a heart to heart with the DM.
Fixing a real issue as soon as possible is a good thing. Preserving consistency and reliability is also a good thing. We must balance the needs of those two things against each other. I very much doubt there is one universal midpoint, but that midpoint shouldn't be abruptly changing all the time.