Concentration, any limitations I haven't thought of?

[MarkVIIIMarc]

I think Hex leads the typical "can you maintain Concentration while doing this" thread. In general though, besides taking damage or casting another Concentration spell what are some surprising things you can maintain Concentration though or some that break it?

[MoiMagnus]

Falling unconscious, like asleep, even for few seconds will break concentration.
[You, see, when after having skipped one or two night of sleep, you sometimes space-out for 1 minute. Well, that would likely break concentration.]

Someone surprising you from behind, almost giving you a hearth attack, would likely count as "taking damages" [and would probably be worth 1 psychic damage]

I'd guess that following multiple conversations at once (or anything pretty hard to do because you have to focus on multiple subject at once) would be made even harder if you are concentrating a spell (since it is one additional thing for your brain to take care of).

[Xihirli]

Falling unconscious, like asleep, even for few seconds will break concentration.
[You, see, when after having skipped one or two night of sleep, you sometimes space-out for 1 minute. Well, that would likely break concentration.]

Someone surprising you from behind, almost giving you a hearth attack, would likely count as "taking damages" [and would probably be worth 1 psychic damage]

I'd guess that following multiple conversations at once (or anything pretty hard to do because you have to focus on multiple subject at once) would be made even harder if you are concentrating a spell (since it is one additional thing for your brain to take care of).

If you surprise a commoner four times, they die.

[Slipperychicken]

PHB 204: "The DM might also decide that certain environmental phenomena, such as a wave crashing over you while you're on a storm-tossed ship, require you to succeed on a DC 10 Constitution saving throw to maintain concentration on a spell."

I'd just say that anything super distracting would provoke the concentration check. That is, things like loud unexpected noises, being jostled, unexpectedly slapped on the back, taunts from someone really annoying, extreme unpleasant smells, and so on. Anything that might fluster you or stop you mid-sentence IRL.

And even if something isn't particularly distracting, if it could interfere with a spell component (especially verbal/somatic) I'd rule a concentration check to represent compensating for it.

[nickl_2000]

There are some spells that cause concentration checks. Sleet Storm in one that comes to mind.

[Draz74]

My DM rules that Readying an Action to cast a spell requires concentration until the spell is released. He seems to think this is RAW, although I don't know where or if the books say so.

[Damon_Tor]

My DM rules that Readying an Action to cast a spell requires concentration until the spell is released. He seems to think this is RAW, although I don't know where or if the books say so.

IIRC, that's correct, but I don't have a book in front of me.

[Eloel]

My DM rules that Readying an Action to cast a spell requires concentration until the spell is released. He seems to think this is RAW, although I don't know where or if the books say so.

When you ready a spell, you cast it as normal but hold its energy, which you release with your reaction when the trigger occurs. To be readied, a spell must have a casting time of 1 action, and holding onto the spell's magic requires concentration.

[Guy Lombard-O]

Being "incapacitated" breaks concentration.

Conditions which include incapacitated are Paralyzed, Petrified, Stunned, and Unconscious (in addition to the incapacitated condition itself).

[J-H]

Having a stone golem jump up in the air, grab the wooden catwalk you're on (30' up), and rip it down.

Did that to my players last session. Concentration was lost.

[Sharqking]

When a player is rife with indecision on their turn in combat, you could have them make a Conc check as they start to lose focus (never higher than a DC 10).

[NecessaryWeevil]

Keep in mind that many/most concentration spells are intended for use in combat, which involves the boom of fireballs, bad guys shooting arrows at you, your own non-conc spellcasting, even your friends fighting for their lives in front of you. If the assumption is that concentration in these circumstances is possible, don't set the bar for requiring checks too low.