I would not do it for resale purposes. For all you know the next owner will slap carpet down as soon as they move in...making all that work and/or expense for naught.
If you are planning to do it yourself, be forewarned that it is a rather nasty job. The big floor sander is really heavy...took my husband and son to carry that beast up the 5 stairs and into our house. And one has to be really careful handling the machine or you will grind big divets into the floor real quickly.
Cannot remember if we had to rent it 2 weekends or 3 weekends. Dusty dirty job.
I applied the floor grade polyurethane finish with a flat, fuzzy pad. Came out nice but was a lot of work.