New ad accounts deliver ~18% costlier for the first ~14 days regardless of creative

New ad accounts deliver ~18% costlier for the first ~14 days regardless of creative

Warm-up = the period before Meta builds delivery history and trust on a fresh account.

Fresh-account cohort, 23 accounts:
— Days 1-7 CPA: +18% ▲ vs same creative on aged accounts
— Days 8-14: +9% ▲
— Days 15+: converged to benchmark
— Scaling budget hard in week 1 extended the penalty instead of buying past it

A fresh account is paying tuition. Hard scaling early just raises the bill.

Read: hold budgets flat for ~2 weeks on a new account; the warm-up tax expires on its own.