With very rare exceptions, my photos requiring the least amount of change during post-processing are my best photos. I typically spend less than 5 minutes post-processing a color photo and about ten minutes post-processing a monochrome photo. For whatever reason, I get caught up in the tonal nuances of monochrome photos more than color photos.
One distinct difference has to do with photos captured in my makeshift studio. It is so makeshift that it is strongly inadequate. That translates into having to spend a lot more time during post-processing (often more than an hour on one image) than I would otherwise have to spend.