If you're running PPC on Amazon, here's a quick breakdown:
By Individual ASINs: Best for tight control and optimizing top performers. Ideal if you want to scale specific SKUs or monitor performance closely.
By Product Category: Easier to manage if you have many SKUs with similar keywords. Great for efficient budget use, but less granular control.
Best Approach: Start broad (category-based), then break out winning ASINs into their own campaigns for better scaling and performance.