I agree. Doing homework now is a great idea. The way I see it is that "old" rubs are not much more than an indication that bucks "were" there. But it is also a good sign of a place to start looking as the fall season nears and progresses. In some 40 +/- of hunting deer in the deep south I can recall only a hand full of times i have seen deer rubbing, and only 3 times that I have taken deer off of a "rub line". But I don't usually set up on them. Instead I use these as a tool to try to find the main trails. So like others have said, look for the trails ... if at all possible between food and bedding. Heavily used creek crossings are usually very good spots to watch. Hunt the edges. Good luck.