One ad account per store
Separate conversion data, separate budgets, separate policy risk. If one store gets flagged, the others keep running. A manager account gives you one login without merging anything.
What can be shared
- Negative keyword lists, where the exclusions genuinely apply everywhere.
- Creative production process and templates.
- Reporting format, so stores are comparable.
What must not be
Merchant Center accounts across unrelated domains, and anything that makes two stores look like the same business when one has a problem.