Questor,
With Winchester AA hulls, I go about 7-10 times per before discarding. Federals don't go as far, and Remington is just a bit less for me. On the other hand, I've got some ACTIV hulls that may exceed this a bit.
What you're looking for, in general, are splits on the skiving at the crimp. When they split all the way back to the start of the crimp you are about done. Other signs of deterioration such as pinholes in the hull above the basewad or looser primer pockets make it a throw away also.
Hodgdon has an excellent article on this in their Shotshell Data Manual where they ran a 12 Gauge through 15 reloads and a 28 gauge through 10 and they tell you pressure and velocity for each of the loadings.
Ka6otm
