Is it a bad idea to only start enforcing rules late in a campaign?

Question

I'm a pretty new DM. My players are almost at session 20 in my first campaign and it's going great.

One of my players has been using a monk. I wasn't familiar with the class, so I'd usually just ask them to explain what their features did. Problem is, I recently made a monk character myself, and realized my player has been doing some things wrong.

They aren't that bad, just things like using loading-property weapons for Extra Attack, doing Martial Arts as a bonus action whenever they want (not just after an Attack action), and counting all their monk weapon attacks as magical (not just unarmed strikes).

For the past couple of sessions, I've started correcting my player, but they've asked: "Why can't I do that now? I've done it before."

It was honestly my mistake that I allowed it before. Is it too late to change my ruling? I don't like countering my player so often, so I'm considering adding house rules for stuff I allowed before I knew any better.

(I haven't actually asked my player if this is even a problem for them yet, but I'd rather catch it early)

Answer 1

As @aaron9eee says, it's never too late to enforce rules as written (RAW).

However, you say you haven't talked to your player yet about it. That should be your first step! Your player clearly knows something is wrong, so take them aside out of game and 'fess up: "I recently found out that we've been handling some of the monk features incorrectly. The game balance relies on us using these features the right way so that everyone can have fun. I'm sorry I didn't catch this sooner!"

(Note: I prefer to use "we" when having these kinds of conversations; it avoids making it sound like you're accusing them of cheating or being "stupid" somehow. And it acknowledges that you could have looked up the rules earlier but didn't, so they don't feel alone in this.)

After that, listen to the player. They'll likely have concerns about what this means for their character going forward, especially if they've made level-up choices based on the incorrect rulings. I'd recommend offering the player a free chance to restat/re-spec by the book. This lets them feel like they're involved with fixing the mistaken rulings, rather than just being punished.

If you're not comfortable allowing a respec, still listen to your player's concerns and do your best to find ways to help them adjust to playing by RAW. Remember, and remind them, that you aren't doing this to punish them. You're doing this because you want the game to be fun and that means making sure you're using the system correctly (or at least, making informed choices about when and how to homebrew).

I actually just had this conversation last week with my players after we all switched to a new system and several folks realized they misunderstood how their classes worked. I set limits on the respec - no complete character concept overhauls, but stat bonus adjustments, feats, spells, etc were all fair game. Some of my players are taking me up on it; I think at least one other is choosing not to because they see it as an interesting challenge to play the character as originally built despite not understanding the mechanics. Either way, the most important thing for my group was acknowledging the issue and agreeing on a solution.

Answer 2

It's never too late to be honest.

I have had a very similar experience, but as a player. I made a tiefling warlock character and being new to 5e I made a bunch of mistakes. Fairly minor things like taking the Magic Initiate feat at first level, and adding the spells on my expanded spell list to my learned spells - instead of just adding them to the list from which I could learn. My DM never said a word.

This went on for a several months until I was helping a friend make a warlock, and she pointed out how I'd been wrong. It sucked. I got real salty for a day at losing all of those spells, but now I feel a lot better knowing that I'm playing 'by the book'.

Have an honest, open conversation with your player. Making mistakes happens when you're new, but fixing those mistakes makes for a better, more fair gaming experience for everyone.

Answer 3

Talk about it, but don't change unless the player agrees

While it can be argued that Rules As Written is the way the game is supposed to be played, and gives you the best class balance, I think more important here is the old saw: "If it ain't broke, don't fix it." While you might have noticed you ruled the Monk differently than RAW, the real question is whether or not that different ruling had an adverse effect on your game.

So talk about it, primarily with the Monk player, but also with the other players, and find out how big their desire is to change that. Since in this case, the Monk would get nerfed, there will probably be some resistance. Which is why you should discuss this with the other players as well, to get their opinion. Because if they don't perceive the Monk as being overpowered, there is not actually a problem at your table.

Once the campaign is done, you can bring the topic up again, and declare that going forward you'll use the as-written Monk rules, but changing rules mid-campaign is not the best idea. For one, if the group is trending towards associated play, a change in the rules of the game turns into a change of the rules of the universe: This is quite obviously a problem from an in-character perspective. The Monk character suddenly can no longer do things he could do before. On the other side, for a more dissociated, optimizing player, this rule change means their decisions of feats is now suddenly the "wrong" one, and if they could, they would have chosen differently. So changing rules mid-game is usually not the best solution.

However, have that talk with the players and find out their viewpoint. Maybe the Monk player agrees that these house rules made them a bit strong and is okay with scaling it back to RAW.