RE: scraps or rubs?
I tend not to focus my efforts on a singular bit of sign or even two signs in the same location. I try to look at the bigger picture in terms of why the animal may have utilized that particular location for that purpose. If you can identify that then you can determine when and/or if the animal is likely to return.
Sometimes a person can hunt over a scrape or rub for days and not see a single deer.
Hope this helps.