Now that I've turned shaving from drudge work into joy, I would feel deprived if I only could get one pass in. For me, it's one pass WTG, one ATG and one XTG. Art's great joy is in the process, not the completion.
A one pass shave can be done, but it won't be perfection. The ideal shave includes at least two passes that cover the entire shaving area WTG and XTG. Some like to go further and add a third pass ATG, or partially ATG.
P.S. I always do two passes plus some touch-ups.
No way for me. Hair grows 3 different ways on neck. WTG, XTG & ATG & a diagonal 4th pass if I absolutely want a BBS.
For complete BBS, I need 3 passes. WTG XTG ATG, in that order
Sounds like reading a one page book to me - but perhaps I am wrong.
Why would anybody want to do just one pass anyway?