Confession time! A recent comment on my Shield Master feat post revealed that I have been playing the Ready action wrong on my table. Ooops! 🙈

So I can use my Action OR my move, you say?
Anyhow, I figured there are a probably a few other folks doing the same, and it might be worth revising the exact text of the Player’s Handbook, as well as some of Jeremy Crawford’s tweets, which are always useful for official rules clarifications, in a bid to get it 100% right from now on.
READY
Sometimes you want to get the jump on a foe or wait for a particular circumstance before you act. To do so, you can take the Ready action on your turn, which lets you act using your reaction before the start of your next turn.
First, you decide what perceivable circumstance will trigger your reaction. Then, you choose the action you will take in response to that trigger, OR you choose to move up to your speed in response to it. Examples include “If the cultist steps on the trapdoor, I’ll pull the lever that opens it,” and “If the goblin steps next to me, I move away.”
When the trigger occurs, you can either take your reaction right after the trigger finishes or ignore the trigger. Remember that you can take only one reaction per round.
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. If your concentration is broken, the spell dissipates without taking effect. For example, if you are concentrating on the web spell and ready magic missile, your web spell ends, and if you take damage before you release magic missile with your reaction, your concentration might be broken.
The Ready action hasn’t seen much use on our table, but when it has, I believe we haven’t adhered to the strict interpretation of the rules, but we have rather used the Ready action to defer our turn until later in the initiative chain, using our reaction as the cost.
HOWEVER, holding your action OR your move, and holding your entire turn are pretty different things. For example, your turn might include not only an action, but a bonus action and movement as well. While your action encompasses literally just your action, and in fact doesn’t even feature the additional attacks from the Extra Attack class feature, which states:
Beginning at 5th level, you can attack twice, instead of once, whenever you take the Attack action on your turn.
The Ready action lets you ready any action you can take, including Attack, but Extra Attack is on your turn. https://t.co/5txJB0u8MH
— Jeremy Crawford (@JeremyECrawford) May 30, 2015
The ruling probably sense: if not for that, you could probably get up to all kinds of tricks and easily lure enemies onto the full force of your offensive arsenal at highly opportune moments; but it certainly makes using the Ready action a much more niche choice than I previously believed it to be.
Even holding a spell is a little dangerous as, if for some reason the trigger doesn’t occur, you lose your spell slot, plus – if you take damage before releasing the spell – you could lose concentration before you’ve even cast.
A readied spell's slot is lost if you don't release the spell with your reaction before the start of your next turn. https://t.co/0K59zeZLjX
— Jeremy Crawford (@JeremyECrawford) August 29, 2015
(Note for DMs: as the spell is actually cast on the Readying creature’s turn, and then held, any successful use of counterspell would need to be at the point of casting, not at the point of release).
How to Use Ready to Good Effect
One thing worth pointing out is that there’s nothing to stop you moving on your turn and taking a bonus action (that isn’t predicated on you taking your Action), and then taking the Ready action. So you don’t necessarily have to sacrifice your bonus action and movement in that round, it’s just you have to take them on your actual turn.
Otherwise, I’d suggest using Ready when you are in a great strategic position you don’t want to give up, and/or for waiting for enemies to get within range of a spell, or short range of a ranged weapon (instead of shooting at disadvantage at long range). These tactics make more sense the less attacks you have! As once you get Extra attacks you will have to sacrifice them when you take the Ready action.
You might, as well, be forced to take the Ready action in order to deal with a ranged foe who keeps disappearing behind total cover after they shoot at you. The trigger in this case would be them reappearing, at which point you could fire off a spell or attack, hopefully disabling the threat before they can attack again. (This is a good tactic for DMs to remember, for dealing with PCs that attempt to use total cover in between attacks!).
I’ll finish with a question: have you been using Ready correctly on your table, and, if so, how have you used it to good effect? I’d be particularly interested to know if it can be used regularly to good effect, as opposed to just for gaining a very specific situational advantage.
Rick Coen
The first few sessions, we had “edition fatigue” and misplayed “Ready”. We had to get ourselves out of the habit of saying/thinking “I delay” and into the mode of “I ready”. We’re pretty good about it now, but as we have hit 5th level and Extra Attack has come into play, the issue (and rules search) popped up again!
Rogues and warlocks don’t really care about Ready – Sneak Attack works on other peoples’ turn, and Eldritch Blast is already awesome. The fighter is a bit more choosey, but in one game the elven Battlemaster has firebolt, so he’ll tend to use that if he has to Ready – 2d10 cantrip is better than 1d8+5 sword.
We do play that you declare an action (not a “capital A” Action), but can *default* to a Move if you choose when the trigger occurs. So “I attack the first enemy through the door” can become “holy crap, I run away from the charging minotaur!”
A great example used *against* our party: I play a Sorcerer who had recently “fallen in love” with Fireball (Empowered). Throughout one module, facing hordes of 2 or 3 HD bandits and soldiers, Fireball cleaned things up nicely. So at the end, when the stymied lieutenant-villain gathered up her allies for a last-ditch ambush, they carefully approached the ruins where we had taken cover from the rain… I saw them in “fireball formation”, didn’t think a thing about them only doing a single Move, and dropped a Fireball on them.
Each of them had declared their Ready as “As soon as Jaxon starts casting a spell, I Dash [out of the area]!” I think I hit one guy who “guessed wrong” about where I was aiming, instead of the dozen targets! D’oh! Doesn’t pay to be predictable!
duncan
I think letting players default to dash if things don’t according to plan is probably fair. I probably wouldn’t make a hard rule (in case I wanted to change my mind!), just judge each situation as it comes.
Haha, nice example of DM strategy there.
Cheers for the insight!
Rick Coen
This came up again last night, as the players waited to ambush an ogre hunter. The Rogue (of course) won initiative, and wanted to “wait until the ogre moves”. I reminded her that she needed to *Ready* an action, not “Hold my initiative”. She chose “When the ogre closes to 30′, I’ll shoot him with my hand crossbow.” Then, because of the actions of the fighter – who stood up out of cover and shot the ogre with his *heavy* crossbow, the ogre stopped, took cover, and threw a javelin — never moving forward into the Rogue’s Readied attack!
She ended up losing her turn in that first round – defaulting to a Dash/Move wasn’t what she wanted to do – which mechanically was the same “waiting until after the Ogre goes”!
Panda
I generally use Readied Actions as written, where you ready a Move or an Action, and that means you cannot use Extra Attack or Bonus Actions when the readied action is taken, BUT I don’t require that the “specific” trigger occur. If you are holding a fireball for when an enemy comes through the doorway in front of you, you can choose to release that spell as a reaction at any time, like when you hear them invisibly sneaking up behind you or you hear them running away.
The only limit is, once I roll their attack (if they attack) then your attack/spell/move will resolve after that attack. If you want your reaction to go first, you have to tell me before I roll.
duncan
Yes, I think giving players some leeway is sensible…. things might not pan out exactly as they planned, but if they’ve cast fireball or nocked an arrow, it makes sense they can let fly in a fraction of a second, according to changing circumstances.
There’s a slight grey area over who acts first in these scenarios. If the PC sets “when they start to attack or start to cast a spell” as the trigger then they go first of course. If they say “when the monster attacks”, you could be cruel and rule that means after the attack is finished, but it would be pretty rare that that was their intention!
PK
I find I use Ready more as a DM than as a player.
Tactically, minions that take cover between ranged shots are fun and make for a good problem the PCs have to deal with at lower levels. But I never have NPC spell casters Ready a spell – they just get targeted by PCs way too much for it to be effective.
Similarly to Rick (above), I allow players to change their Ready action based on circumstance and being reasonable – Minataurs coming through the door are something you run away from!
duncan
True, Rick also gives a good example of the DM using Ready, so maybe it was Jeremy Crawford’s evil plan, after all, to slip this action into the PH!
DM David tweeted my post, and there was also a conversation over on Twitter
https://twitter.com/dmdavidblog/status/1353449664838832129
An idea came up which might get you to rethink enemy casters and Ready! And that is have the evil wizard cast their spell at a range of 90 feet, then move 30 feet and release it at 60 feet using their reaction. Thus avoiding the players casting counterspell 🙂
Dain
As a player, having a default ready action dodge when out of combat exploring is often handy. As a dm, having readied attacks not only counters PCs jumping in and out of cover, it is a good way to deal with those pesky owl familiars.