Insights Into the Daf says that Mar brei d'Ravina needed seven separate sets of clothing so that when each one was washed, it would not be worn until eight days had passed, to avoid white lice. But if there were seven sets of clothing, and one was washed each day, it would be worn after six days had passed (in fact five- worn on day one, washed on day two, and then I assume the first day we would count would be day three). Wouldn't Mar brei d'Ravina actually have needed not seven but nine or ten sets of clothing?

Daniel Moskovich, Kyoto, Japan