# Refreshing a DoT early blends the old and new instances instead of simply replacing or stacking them

Reapplying the same DoT before the previous instance expires combines the two: the new DoT's total is the old DoT's remaining value (scaled by its remaining duration fraction) plus the new application's full value, merged into a single instance.

Diablo IV patch 3.2.1. Category: snapshotting. Evidence: Confirmed.

## Detail
This matters directly for snapshot value: refreshing a DoT while it still carries a strong old snapshot (e.g. a Vulnerable-boosted tick rate) blends that old value forward into the new instance rather than discarding it outright, so early refresh is not necessarily a downgrade even if your current buff state is worse than when the DoT was first applied.

## Why it works
The formula given is: new combined DoT = (remaining duration % of the old instance * old instance's total) + new instance's total, recombined into one targeted DoT rather than two separate stacks.

## How to use it
Do not reflexively avoid refreshing a strong snapshot early out of fear of 'losing' it - the blend formula means some of that value carries into the new instance rather than being fully discarded.