I think it depends on what you think looks right. In my very old house I have places where walls were moved and the floors have visible repairs, and it does not look bad, at least in my opinion. If you refinish the floors at the same time, the different boards will blend quite well -- while leaving the tale of the previous incarnations readable for those who know. If you put an area rug over the joint between the regular floor and the repaired area, even if it doesn't cover the whole spot, it will serve to trick the eye into not seeing what you don't want to highlight.

On old floors, it's a fool's errand to try and get ultra-perfection after they've been lived on for three-quartes of a century. You can tidy up the worst dings by filling nail holes with tinted wood putty or even using dutchman-type patches for real divots or blown-out knot holes. But the "look" that owners of new-material floors crave is the look you've got right now. It would be sort like having a face lift, then painting on crow's feet to give your face gravitas. Cheaper, better and more handsome to leave it as it is (after refinishing, if you'd like to unify the look). I am in the minority in preferring to not use polyurethane (water-based or not) as a floor finish. For pine I would use tung oil and wax, but that is an un-common choice.

Good luck.

Molly~

If the repaired floor has minor gaps, up to 1/8 inch wide, you can fill with epoxy and sand smooth. Just be certain that the epoxy is tinted to match the flooring, or possibly a bit darker than the finished floor. If the filler is lighter than the surrounding floor, the gaps will stand out and look bad.

Filling gaps along the long sides of the floor boards is one thing that I would be very cautious about, especially as we are just coming out of the dry heating season. I'd certainly wait until full summer to see if the floor boards swell back up and close the gaps. If you filled gaps when they were open due to low humidity, then when they swelled in summer, the edges of the boards get crushed. This can cause them to bow up along the edges, ride up over each other, simply smash the edges together resulting in larger cracks with each successive cycle. End grain gaps can be filled with less risk, though.

Molly, you have such a lovely way with words, and very good information as well. My floors have wide gaps and I won't get to the floor until at best summer.

Sadly, I think that I am going to carpet our upstairs rooms (kid's rooms) the floors are gouged and splintered and in sad shape.

Thanks for the wisdom all, I am tired and would like to add more but for now, goodnight.

Here is a link to the most informative site I've seen.

Here is a link that might be useful: Sanding site