It depends on how close of a shave you want. If you simply want to be presentable you can do one quick pass "with the grain", but if you want a perfectly smooth

It depends on how close of a shave you want. If you simply want to be presentable you can do one quick pass "with the grain", but if you want a perfectly smooth shave you can do several passes (perpendicular and against the grain). If I'm in a hurry I can shave in 5 minutes (though this is a good way to cut yourself), if I'm taking my time it's maybe 10 minutes. I also only shave every other day, in large part due to how close of a shave you can get, though I also naturally don't grow hair quickly.