Lots of work, but worth it. Love the way it looks with the Waterlox finish. Took 4 coats and a week and a half to set (the weather was rainy so we had to wait a couple days in between so it would dry properly.
Original pine plank floors in 100+ year old house. Painted at some point with multiple coats of paint. Some linoleum.
After 3rd day of sanding. We took our time and were religious about vacuuming constantly to keep the dust down.