# Overpower stacks require active refresh maintenance - each stack silently expires on its own 4-second timer

Because each Overpower stack carries its own independent 4-second duration rather than the whole buff sharing one timer, a build must land a new Overpower-triggering hit roughly every 4 seconds PER STACK slot to avoid stacks quietly falling off before you notice.

Diablo IV patch 3.2.1. Category: uptime loop. Evidence: Confirmed.

## Detail
This matters more the higher your effective stack cap is: a build pushed to 16 stacks (see season15_ritualist_overpower_extension) needs a much higher sustained trigger RATE to stay near its cap than a baseline 4-stack build, since more stacks are simultaneously counting down.

## Why it works
Stacks are tracked individually rather than as one pooled counter with one shared timer, so refresh frequency - not just occasional triggering - determines your realized average stack count.

## Numbers
Each stack: 4 second independent duration.

## How to use it
For high-stack-cap Overpower builds, prioritize skills/Aspects that guarantee frequent Overpower triggers (rather than a rare high-value proc) to keep the stack count near its ceiling instead of oscillating.