I think a lot depends on the case design and the "dress code" one is wearing, I can easily imagine a dress watch 38-41 mm without issue my GO chronometer seems sometimes even small, while sports watches are hardly less than 40mm with the exception of the AP Jumbo 15202 at 39 mm it has the perfect balance of size, weight, thickness, lugs,... every time I take it off and put on my Radiomir it feels REALLY weird for few hours then there is nothing more comfortable at 45mm. Conclusion, it all depends how much affection one has to his watch size would not matter.