Meta puts the most budget on the worst-converting day | Samet Durgun, the Growth Therapist

Our Meta budget runs two days behind our customers.

We run ads for a health app. Motivation peaks when the week starts, and the data agrees: Sunday and Monday installs convert best. By Wednesday the moment is gone.

Does Meta spend the budget on the right days. Installs that become payers by day of week, average 7.00 percent: Monday 7.14, Tuesday 6.88, Wednesday 6.63, Thursday 7.04, Friday 6.80, Saturday 6.98, Sunday 7.57. Share of the week's spend by day, even split 14.3 percent: Monday 14.0, Tuesday 15.0, Wednesday 15.3, Thursday 14.7, Friday 13.3, Saturday 13.7, Sunday 14.0. The most money sits on the worst day.

209 days, 346,317 installs, daily attribution data, one health app account. Wednesday converts worst (6.63%) and gets the most spend (15.3%). Sunday and Monday convert best (7.57% and 7.14%) and get the least spend (14.0% each). Pooled test p < 0.00001, holds on both halves of the data and both platforms.

Tbh, I won’t villainize Meta. Across the accounts I run, Meta does adjust toward the good days. My read: conversion signals the change with a delay, so the reaction to a good Sunday and Monday arrives midweek. The system keeps catching up to a moment that already passed.

Our fix is manual: a weekly budget shape that leans into Sunday and Monday and pulls Wednesday back. Worth about three extra payers a week on pooled rates, an upper bound, for the cost of a weekly manual change.

A lifetime budget with ad scheduling could hand this back to Meta in theory. I do not trust lifetime pacing with a pattern this specific. If you do, I want to hear the case.