Q:I have floors that are not in bad shape but could use some refilling and a new coat of poly applied. Is it okay to lightly sand the floor, use a putty to refill cracks, and then reapply poly?
A: I would fill the cracks as you mention, but try to remove as much of the filler residue from the floor surface of surrounding boards as much as you can, while you are doing the filling. Then, the entire floor has to be abraded, cleaned and coated. If you want a filler that boasts the claim not to crack or fall out, take a look at timbermate.