That's where years of experience must help a lot.
My first pass is ok, the second is better but I don't get BBS until 4 passes and then there's the clean up which is mostly on my neck.
I go down - sideways - up then down again, then the cleanup.
If I got to hone it and strop it I might as well give it some exercise :D
Years down the road i will probably be able to do one pass only but I sort of hope not, I love to shave and don't want it over too quickly.