This official D&D rules clarification video was posted on youtube yesterday and I decided to do a quick recap. Why not? I constantly forget rules, so this seems like it will help me.
I did once write a "forgotten rules index" to help myself with things I just can't keep straight, such as concentration and underwater combat. It will be interesting to see what's covered on this show.
This show is hosted by Greg Tito and Jeremy Crawford. Jeremy says that he thought it might be a good idea to actually go through the Player's Handbook to see what's in there. Even he forgets some of the things that are in the PH.
Jeremy says that the Dungeon Master's Guide is "wall-to-wall goodies," but right now he wants to go through the Player's Handbook to highlight some rules that people have forgotten.
Specific Beats General: If two rules conflict with one another, the more specific rule always overrides the more general thing. The game is exceptions-based. The game is build to "accommodate surprise."
I honestly can't think of one time when I've ever had this come up in D&D.
Round Down: If you ever have a fraction in D&D, you round down. Jeremy says he gets this question all the time. Jeremy thinks that, looking back, fractions don't come up too much in D&D and so when it does come up, it throws people.
This rule was burned into my brain in 4th edition.
Proficiency Bonus Rule: You can never add your proficiency bonus to a roll more than once. For example, if you are proficient in playing a piano and you are proficient in performance, you do not add the proficiency bonus twice.
Greg points out that, if you're a rogue, you do get a doubled proficiency bonus in some instances. That's a case of "specific beats general," says Jeremy.
Jeremy calls this next one one of the most-missed rules. In the section about Armor Class...
Calculating AC: If two or more things in the game give you different ways to calculate your armor class, you use only one of them. You do not get to add them all together.
So, if you put on a suit of armor, which gives you an armor class calculation, and you're a barbarian who has the unarmored defense ability, you don't get to do both. You pick one. Jeremy assumes that you will pick the one that gives you the best AC.
Jeremy says that he didn't realize back in the beginning of 5e how much this would come up.
The hosts note that there is a big section in the Sage Advice compendium pdf on this topic.
Jeremy says that he doesn't get frustrated being asked these same questions all the time. The fact that he gets the same question means that lots of new people are jumping in to the game every single week.
That's it! Short, but useful.