Just posted this a few days ago, but here is what I do to get 6-12 months from a cheap gillete sensor excel blade. A pack lasts years.
When done shaving, pad dry, don't rub it or it will eventually break to pad that keeps you from shaving to close. Then put the blade into oil. I use vegetable oil.
To sharpen (every 3-4 weeks or so), get an old pair of denim jeans, and lightly run the razor back and fourth 10 times in each direction. Once again, don't apply too much pressure or you will break that pad that keeps you from shaving to close, then the blade is ruined.
That's it.