Thanks... That's exactly what I was looking for. That particular area is very high traffic. It's sort of the merging of three rooms... Two of which get used a lot in the course of a day X 15 years.(only one bathroom in the house) The poly finish in the dining room and bedroom looks almost new.... High gloss. Living room is still in good shape although perhaps a little dulled but definitely still looks great. When we refinished the floors back in the day... The maple was natural color but I wanted a darker wood floor so we stained it a medium cherry. The color has held up very well... Until you move a large piece of furniture like the bed then you can tell the floor open to the light has faded a bit. Fortunately my furniture doesn't get moved around too much so I don't really notice it. Since 95% of the floor is still in almost pristine condition, I wasn't planning on a major refinishing for quite a few years. And to answer your concerns.... No moisture issues to the floor in that area. I think just a lot of wear and tear. Another plus to that area is it's a rather dark area of the house so a slight difference in color or gloss probably wouldn't be that noticeable. One more question... How lightly to sand and what grit? For applying poly, I believe I used a lambs wool applicator the first time. Something like that work again?

Spot repair using polyurethane is problematic since the finish does not 'feather' well. That means the finish does not blend with existing surfaces in a repair area easily.

So, what I have successfully done on several occasions is to start with 100 grit paper(I favor a random orbit sander) and get the big problem areas smooth and chip/flake free. Don't worry about defined edges, just get the problem spots.The random orbit sander is much faster than a 1/4 sheet sander.

Then switch to 150 grit paper and get the sanded surface smooth.

You want to use the same type poly as when you refinished. Use a rag dampened with paint thinner(if you are using oil based poly finish) or water(for water based poly) and remove all the dust/etc.

Apply the poly on the sanded area, using only enough to cover the sanded area. For that small area, a paint roller with a thin nap(thicker naps will cause bubbles)---1/4" nap is fine.

Now for the blending/feathering. I use a cotton Tshirt as the feathering tool. I use a piece about 12" square or 6" wide and 12" long. I fold it until it makes a ball with a smooth surface. I dip it in poly and begin wiping the edge of the fresh poly in a circular motion, moving outward until the pad is dry. Then move back into the fresh poly and keep up the blending until the entire perimeter is done. You do not need a lot of pressure. And you will find the best method of wiping as you proceed. Since you will need three coats of poly to complete the repair, you will be able to lightly hand sand the perimeter before another coat.

i would probably start with steel wool, and do it by hand and see if you can get all the flaked poly off, if thats not working then you could go a random orbital with 150, but dont put too much pressure on it, the idea is not to take stain off,

after that just brush a light coat of finish over the area and let it dry, come back the next day lightly scuff with 150 or 220 grit paper and brush another light coat, stay on the sanded area, dont brush finish outside of what you sanded originally. then repeat the scuff steps and brush one more coat of finish, let dry. then i would scuff everything again and this time go 4-6 inches outside of what you orginally sanded, and then apply the last coat of finish and feather out your brush strokes into the area you never touched.

in a few weeks of normal traffic the area should blend in nicely and will hardly notice any work ever took place....if you did it right ;)

Your going to want to do something before the stain is affected that is for sure. The stain is the hard part to match. I disagree that poly doesnt feather, it has decent self leveling, depending on how long you take and if you do touch ups while its half dry or not. Poly is something you apply and leave alone till dry. The more you mess with it while its drying the worse it will end up.

Get off the flaking poly then apply the new poly with a matching sheen, feathering out the poly on the edges. If the new poly makes a noticeable edge it can always be sanded smooth and followed with a thin coat of poly to get the sheen correct in that spot. It will be noticeable it is new in that spot but it takes probably half a year for it to start looking the same.

Thanks for all the great advice.... Doesn't sound like it should be too difficult, and it's really not a very large area. I took another look at it and it's probably only in about a 3'x4' area. Also, the flaking is quite random.... Little spot here and another spot a few inches away. I'm not generally a very handy person when it comes to thIngs like this.... But I figure if it really goes badly a throw rug will cover up all the evidence.