After sanding and stain, the finish is what protects your floor for the next decade. The two main families are water-based polyurethane and oil-based or oil-modified finishes, and each has real trade-offs.
Water-based finishes dry clear and stay clear, so natural and light-stained floors keep their color. They have low odor, dry fast enough for multiple coats in a day, and professional-grade products like Bona's are very durable. They're our usual recommendation when you're living in the home during the work.
Oil-modified finishes add an amber tone that deepens over time. Many people love that warm glow on red oak and in older homes. The trade-off is a stronger smell and longer dry time between coats, which usually means planning to be out of the house for a day or two.
Sheen is a separate choice. Matte and satin hide scratches and dust and look more modern. Semi-gloss and high gloss show off the grain and reflect light, which can be beautiful in a bright room but highlights every scuff.
We'll lay out finish samples on your sanded floor so you can compare color and sheen in person. There's no single right answer, only the right one for your house and how you use it.