A proper refinish is a sequence: coarse cut to flatten and strip, medium cut to remove scratch pattern, fine cut to prepare for finish, edges and corners by hand, then a screen or buff between coats. Skip a step and it shows in the finished floor as swirl marks, dish-outs at the edges or waves under a window in raking light. We run every step.
We use dust containment on our sanders so the house stays livable and the finish goes on clean. For finishes we work with water-based polyurethanes, oil-modified polyurethanes and hardwax oils, and we will recommend one based on how the floor is used, the look you want and how quickly you need to be back on it.
Old floors in the South Sound are often red oak or fir with a few generations of finish on them. Most have plenty of wood left to sand. We check board thickness before we start and tell you if a floor is on its last refinish.