Two
I've been using the Bic Metal for more years than I can count. They last me 4-5 shaves before I can feel the edge lose its sharpness; in a pinch I can get up to ~15 shaves if I really need to.
I like them because they're cheap, they give a quality shave (first 4-5 uses), and -- most important to me -- they're really
narrow front to back which allows me to get a really close shave on my upper lip just below my nose. I can't seem to do that with a multi-blade razor.
I'm also a big fan of Proraso shaving cream on a badger brush.
