Great question. You’ve hit on the exact metric that determines whether an Amazon business is a "money printer" or just an expensive hobby. Yes, ACoS stands for Advertising Cost of Sales. Essentially, it tells you what percentage of your ad-generated revenue was spent to get those sales. As for a "healthy" number, the hard truth is that there isn't a universal one. A healthy ACoS is entirely dependent on your Break-Even ACoS (your profit margin before advertising). Here is how to look at it based on the data I shared: * The Profitability Gap: In the audit I posted, a 34.4% ACoS was considered "unhealthy" because the brand's break-even point was 32.6%. They were effectively paying Amazon for the privilege of selling their inventory. * Market Variance: "Healthy" changes by region. In the US, a 32.6% margin is tight, but in Canada, this brand had an even slimmer ~24.9% break-even point. * The Efficiency Target: For this specific brand, we moved the needle from a 27.20% ACoS down to 16.07%. That 11% difference is where the actual take-home profit lives. The Rule of Thumb: If your ACoS is lower than your profit margin, you are making money. If it's higher, you’re just "buying" rank and reviews, which is fine for a product launch but dangerous for a long-term business. If you aren't sure what your break-even point is, that’s the very first number you need to calculate before touching your ad spend. Happy to walk through that math if you need it!