The short answer
Within a day or two of going live, Meta picks a winner and puts about 90% of the budget on one or two ads: run ten, and one takes nine-tenths of the spend. That is normal, so leave it and turn nothing off. The one job left is checking that the winner brings merchants who fund rather than cheap leads. A $10 lead that funds nothing is not a winner, and that is the only reason to switch one off.
Upload ten creatives, check the account two days later, and the spend looks broken: one ad has most of it and the other nine have almost nothing. Brokers react by pausing the nine, or by switching the one off to force the budget elsewhere. Both undo the thing Meta is doing on purpose.

| What you see | What it means | What to do |
|---|---|---|
| One or two ads take about 90% of the spend within a day or two | Meta has found the creative that converts on your event | Nothing. Leave it running |
| The other ads get almost no spend | They are what Meta can shift budget to later | Leave them on — up to fifteen live at $100 a day |
| The winner’s leads fund deals | A true winner | Squeeze it, and start on its variants |
| The winner’s leads are cheap and fund nothing | Meta is finding the wrong merchant efficiently | Turn that ad off, and check the pixel |
Why you leave it
Meta is not failing to spread the budget. It is concentrating the budget on the creative producing results on the event you send back, and it can still move that budget later as the winner fades. We very rarely turn ad creatives off for that reason: Meta knows what it is doing. The six angles write-up from the first video makes the same point from the other side: Meta pushes the spend to the ten to fifteen percent of ads that work, and starving the rest is the algorithm doing its job.
The one limit is the size of the set at the floor. At $100 a day, Alex’s ceiling is fifteen creatives live at once, because too many on too little budget means nothing learns. So at that budget, the ads Meta has stopped spending on are the ones that make way when new creatives go in. Above it, leave them.
The one reason to turn it off
A true winner is not the ad with the cheapest leads; it is the ad whose leads fund. It is easy to get caught up in the numbers in the ads manager and celebrate the creative producing $10 leads all day, when those leads are bad and nothing is funding. That is not a winner. If Meta is still sending that ad the whole budget, switch it off and use your own judgement over the algorithm’s. Plenty of leads is the first step of a winner; the test of one is what funds.

The winner will not last
The ad that works today will not work in two months. The more you spend, the sooner it fatigues, because it is shown to more people more often, and the burn scales roughly one to one: double the spend, double the creatives. So the time to replace the winner is while it is still winning. Make ten variants of it before it dies, and keep the creative pipeline sized to the budget.