I seem to strike this problem too with a lot of frags. It's always disappoiniting when a frag you fall in love with turns out to be poor longevity. I don't have the time or ability to respray in the afternoon.
I've decided to cut my losses and stick with ones that have proven longevity on my skin. So if I love GIT but find it doesn't last long enough, I just won't buy it. Plenty more frags out there...
Examples of frags which don't last long on me would include Bvlgari PH and L'Instant PH - I absolutely love them but they just don't last.