Hardwood floor sanding is always a big challenge for every flooring expert because it requires much more work than usual. The floorboards, the subfloor, all the gaps. It's a big list, and when it's an old floor, it may take days to achieve the desired result.
This time it took 3 days to make this flooring like new because it was in good condition, we had to do small repairs, filling a few gaps, and that's all. No staining, but refinishing was a must.