How do you remember every instance?

[Zigabar]

Condition 1: adds have more HP than boss - kill boss
Condition 2: boss has more HP or HP regen via add: kill adds
Condition 3: add brings KO mechanic: KILL IT NOW!!

Condition 4: Adds and boss: Mage LB all the things.

[SendohJin]

if you forget you forget, you die to it one time and it should come back to you.

[Khubla_Kha]

It'll come to you with repetition as with anything where doing the same thing over and over. If nothing else muscle memory normally saves me when normal recall fails.

[ExKage]

Some of them just become muscle memory or other times there's really only one or two things that need to be remembered. I occasionally can never remember what voice or purple/blue is in/out for Cutter's Cry.

Sometimes it is hard to just list mechanics though but when/if it comes up I usually say something like "X Y Z are the mechanics. Don't remember if I missed any?" and someone else in the party will chime in. I have never had issues with someone saying they're new or forgot something. It's always when people not mention something and then things fall apart that it becomes "a thing."