Oh, absolutely, I keep track! I use all the points to spend for "free" holiday gifts for the family. I've been using a card which has rotating 5% cash back categories (gas, grocery, amazon, etc), so I try to tie my purchases to buy enough needed supplies of things like cat food and litter to make it until the next time they get 5% cash back.
I also keep a list of amazon purchases (including holiday gifts and things I want but don't need immediately) and order them all in the fall when the Amazon 5% cash back period comes around.
Also, the card offers 5% cash back at Walmart pretty much always, as long as you shop online.
The extra mega bonus is that I managed to snag a CashBack Match from them two years in a row, through fortuitous circumstance. That menas they double whatever cash back I earn in the year. So the way I look at it, if I shop smartly, it's like I get to save 10% on whatever stuff I buy (5% cash back x 2). EXCELLENT.
So, with all that, I probably earned about $800-900 cash back last year. I don't know for sure, because I spent some of it in the spring before I started keeping track. I got a new sewing machine out of it, though, as well as crafting supplies to make homemade christmas presents, and on top of that I still had about $600 in cash back in October to waste on "free" holiday gifts. :)
(I know, I know, I could have invested it, but I love Christmas and my extended fam is spendy)