An acquaintance of mine got about half of a gymnasium floor maple wood for cheap. Thought he would save a bundle by planing the surface and essentially getting new wood.
He used one planer to get the worst of the finish off, some of which was paint, and another planer to get a decent finish. He hired a helper at $20 an hour.
After he was done he decided that it would have been far less expensive to simply buy new maple pre-finished flooring.
So maybe for a small amount of wood for yourself, it may be worth it.
I did about 50 square feet of old growth Douglas fir 1 1/2" thick T & G from a floor, only because there was some excellent edge grain wood there. I checked with my metal detector first and still missed one piece of a broken off drill bit buried in the wood.