If there's any really heavy work still to be done (equipment installation, work where they might be using high-lifts or forklifts) or any messy work (plastering, texturing, painting with something other than latex), you might want to wait. If only light-duty stuff remains (painting or wall work on ladders and scaffolds, electrical, plumbing etc.) you can go ahead and do it now, weather permitting. I'd allow at least 30 days cure time before you do anything that might scrape, scuff or lay paint/plaster stuff on the floor that will need to be scrubbed away.