As I spray a frag around 8am I'd like it to last the whole working day (e.g. til around 6pm). In other words, I'd like the frag for during the day to last about 10 hours. Then, after dinner, I usually apply a different frag as my SotE. I don't really care how long those last but ironically enough the evening frags usually have better longevity than the dayfrags.