This might not be what the manufacturer recommends, but it's the way it's done in most households. Except I would tend to forget where the rest of the blades were put, and ended up using the first one for as long as possible. Now I just buy a bag of non-refillable disposables, and the rest of the bag disappears among the family. From Doghouse Diaries. Link
And even if you don't go with a straight razor, a proper brush for applying shaving cream can make quite a difference.
I keep meaning to write up a blog post for a friend with the benefits, not only monetary, of using a safety razor.