I've been working on a small (9X12 or so) floor for about a week. Pulled up carpet, the wooden strip along the edges, the nails, staples... then rented a drum sander. Used it timidly (since I've never used one before) 80 grit and 100 (it's what the rental place had) Also rented an edger that seemed to fly off and go where it wanted. Bought a little orbital sander to go over the stuff that the rental sanders missed (they missed plenty...because I was afraid I might wear the floor down to nothing) Finally bought some 50 grit to get the stubborn areas and used the orbital sander at an angle after reading something about that on here. I plan to continue sanding with some finer grit as well...

My questions are:
1) do I need to get every scrap of old finish off or is it going to look okay if there are a few shadows of the old stuff... not much, but some here and there?
2) I'm thinking of putting polyurethane on it without staining it. Any opinions on how that will turn out?
3) I live in Florida and whatever the drying time might be elsewhere seems to take WAY longer here... even with the AC on constantly. I hesitate to use anything known to take very long to dry but I heard that the water based Varathane scratches easily. I'm right next to the beach so there will be a fair amount of beach sand coming through the house. Suggestions?

Thanks,
Kathy

Stain usually does a good job of making any faded areas less noticeable. If the overall color of our floors are uniform and you like the color, then there is no need to stain. You should still do a test area to see what the final color will be with the finish on it as the finish could change the color.