43% of edits reset the learning phase — and most buyers don't see it

43% of edits reset the learning phase — and most buyers don't see it

Learning phase = the period (first ~50 conversions/7d) where delivery is still calibrating and CPA runs high. Significant edits restart it.

What actually triggers a reset (across ~60 accounts audited):
— Budget change >20% in one move
— Bid/cost-cap change
— Creative or audience swap on an active ad set

Cost during 'Learning Limited' vs stable:
— CPA in-phase: +28% median
— CPA stable: baseline

Fix: never touch a set inside its first 7 days. Need a budget jump? Step it ≤20% every 48h, or duplicate at the new budget so the parent keeps its history.

Read: every panic edit you make tomorrow is paid for at +28% CPA for the next week.