Explanation
Testing properly requires enough variants that most of them lose, which is arithmetic rather than philosophy: below about six versions, normal variance in short-form distribution swamps whatever difference you were trying to measure. Whether that is possible depends entirely on this number.
It is also the figure missing from most reported returns. Platform ROAS excludes production, so a campaign running forty assets can look efficient on media and lose money once the creative is counted.
The common mistake
Counting only the direct cost. Briefing, revisions, approvals and the licensing admin are all part of what an asset costs, and they are the parts that scale worst with volume.