How I set the test budget

At the same budget, every dollar a new ad spends comes out of one that sells. And Meta counts adding a new ad to an ad set as a significant edit that sends the ad set back into learning. So new ads never go into the ad set your winners live in.

1. Tests get their own budget. New ads go in their own ad set or campaign, with their own budget.
2. The cap is a fifth. All test spend together stays at or under 20% of your daily budget. The other four fifths stay on what already sells.
3. Each idea gets about one sale's worth of spend a day, for 7 days. Less than that and you're judging noise.
4. More ideas than slots: the most different go first. A new buyer, a new reason or a new format goes before a small twist on something already running. The rest wait for a slot.
5. A test that passes both [winner tests](/resources/winner-tests) graduates. It moves into the main budget, and its slot goes to the next idea in line.

Test budget per day = daily budget x 0.2
Ideas testing at once = test budget per day / your cost per sale
Each idea: about 1 sale's worth of spend a day, for 7 days

This matters more with AI ads, because you can make more than you can test. Above a fifth, I've watched tests drag a whole account below its target. Under it, a losing idea costs you one small slot for one week.

Testing only pays when the winners can keep funding it.