I did it for my DD, and it wasn't that hard. I ended up having to take more foods out to get her to a baseline (vs. doing something like Dr. Sears TED where you start out with little to get the baseline, hopefully, and then add back in). However, it says (I think) that it takes 10 days or something like that. You cannot add in a new food each day. You have to wait 3 days between new foods, 4 if you're checking a breastfed child (I'd actually recommend 7 days to be sure). Skin symptoms take a little longer, in my experience, than other ones, to get, and then to clear. So you want to make sure something is out of the symptom before you add in the next one or then you don't know which food caused the reaction. But I thought it was a great place to start. I'm doing it now, but I'm giving it 2 weeks on nothing first, before I start adding foods back in.