Wow, you guys must have some tough floor and/or are really on top of keeping the nails trimmed. I have a 100lb German shepherd and a 15lb beagle mix. Our wood floor look fine until the sun hit it a certain way. Then you can see all the scratches. We are not very diligent in keeping the shepherd nails clip mostly because he doesn’t like it and puts up a big fight (we have been taking him to the vet lately to do it and it takes 4 people to hold him down) where as the beagle could care less. That being said, I still know all it takes is to get them refinished when the time comes and any dirt that the dog track on it is easy to clean. On the other hand, watch out with carpet! Both dogs as puppies have found areas they decided to rip up, and it sure sucks when the muddy paws get on the carpet.
I would also say if you have stairs that go down to a wood floor, you would be wise to put a rug there. Our shepherd likes to launch from about 5 stairs up, or turns the corner real fast and would always wipe out. That doesn’t happen with the rug there and hopefully that will save us from a very expensive ACL surgery someday.