One Amazon PPC specialist who does it all, not four who rotate.

Supplements is one of the most expensive categories to advertise in. It's also repeat-purchase, so a 30% ACoS on a first order is worth more than it looks.

Six years with the same person: spend roughly doubled from year one and held there, with ACoS kept in range through every Prime Day and Q4.

Most accounts get less efficient as they scale. This one went the other way: in 2025 and 2026 spend rose while CPC held steady and ACoS flattened, which is what I'd point to if you asked what six years on one account buys you.

That's harder in fashion, where one product can have dozens of child ASINs bidding against each other and high returns make ad revenue overstate profit.

As a new brand, it ran above 300% ACoS in its first months while it built initial rank. By mid-2023 it was under 30%, and it has held there for three years while sales kept climbing.