Warrior Newb

[Spoekes]

Capping accuracy means having enough to never miss for a certain fight. To get through all of Coil without missing as a tank, you'll need 558-ish. Missing at all is terrible not only for damage output but for enmity generation, meaning you'll lose aggro to others more easily.

missing is especially terrible because most of the time it interrupts your rotations.
If you never entered T5 yet but have full POE gear + zeta chances are high you don't need to worry about it at all until you reach the last Turns.