D&D 5E Turns and Rounds; it's what my brain's doing!

[Charlaquin]

Yes, very true for me. I only just got it by posting here after reading the reddit Q&A.

In my brain, once per turn meant once on my turn. Thanks everyone for the clarity.

Does this imply that reactions are highly significant, because only they can grant another use of all these "once per turn" effects per round? And I guess from what everyone has said, they are they only mechanic that does this? So "once per turn" really means possibly twice per round dependent upon reactions? Not more than twice?

Unless you have some feature granting you additional Reactions. I don’t think there are any such features available to players in any published material, but some monsters get multiple reactions (hydras, for example), and Legendary monsters can often act off-turn with Legendary Actions, and there’s always the possibility of DMs making custom magic items or whatever that might do it.

I would say that yes, reactions are extremely important. Opportunity Attacks potentially allow you an additional Attack each round, which can have a significant impact on damage output. That’s why Polarm Master is such a powerful Feat, by making it easier for monsters to provoke Opportunity Attacks, you get consistently higher expected damage per round, even without any once-per-turn attack riders. I also feel the Ready Action is a very powerful and under-utilized tool in the players’ arsenal. I’ll also occasionally use the Facing rules from the DMG, which make Reactions especially important, since you use them to change Facing off-turn as well.

 

[guachi]

You only get one action and potentially one bonus action on your own turn, and acting when it’s not your turn requires you to use your Reaction, of which you only get one per round.

I see this stated over and over again and it's just not true. This is what the rule says: When you take a reaction, you can't take another one until the start of your next turn.

It says nothing about only getting one per round. If it's the first round of combat and someone goes before you then you could use your reaction before your turn started. Then at some point you get to take your turn and now you can take another reaction. Perhaps you used it later in the same round during some other creature's turn. Now you've taken two reactions in one round something you claim can't be done. You can do this on any round of combat where a round starts and you still have your reaction.

Or you could be a sufficiently high level Thief and get two turns in the first round of combat potentially giving you three reactions in one round.

 

[Charlaquin]

I see this stated over and over again and it's just not true. This is what the rule says: When you take a reaction, you can't take another one until the start of your next turn.

It says nothing about only getting one per round. If it's the first round of combat and someone goes before you then you could use your reaction before your turn started. Then at some point you get to take your turn and now you can take another reaction. Perhaps you used it later in the same round during some other creature's turn. Now you've taken two reactions in one round something you claim can't be done. You can do this on any round of combat where a round starts and you still have your reaction.

Or you could be a sufficiently high level Thief and get two turns in the first round of combat potentially giving you three reactions in one round.

Sure. That’s actually true of pretty much everything that we tend to refer to as per round in 5th edition. 5e almost never refers to rounds; spells don’t last one round, they last until the start or sometimes end of your next turn or the target’s. You repeat saving throws for ongoing effects at the start of your turn, not once per round. Limited abilities aren’t once per round, they’re once, and you regain the ability to use them at the start of your turn. Referring to such things as “once per round” is just common parlance, much like we might say you get a certain number of spell slots “per day” when really you just get a certain number of spell slots and regain them when you finish a long rest.