My wife and I bought a house seven years ago and found that it had nice hard wood floors under the old wall to wall carpet. We ahd spoken to a professional floor refinisher. And he told us that he sands the floors with a professional floor sander. He stated that his sander is far superior to the ones that you can rent at the rental distributer. He did not have alterior motives to give us advice such as he doing the job, because he was on the other side of the state. He said if we rented one of these lighter rental units we would work with it for an hour or two and then would be calling a professinal in anyway. This would be because of the gouges that one ends up putting in the floor with these lesser quality sanders. I have had some expereice stripping furniture. So we went ahead and chemically stripped our floors. This did not even out the floors the way a sander might but it did a good job. The floors maintain the chactor of thr home which was built around 1917. We refinished the floors with ployurathain. Note the powerful chemical strippers are toxic.And proper ventalation is necssary. The powerful compounds work the best. Read the directions and do not use them aroud children or pregnant women. We did three large rooms in 4 or 5 days.