I beg to differ that alu. is not reloadable.
Two summers ago I made an experiment using boxer primed, CCI, alu cases. It is possible and it did work for the 4 consecutive reloadings of 5 cases till I ended the experiment. The loadings were in the mid range for powder charge. So, yes it is possible, recommended, NO, do so at your own risk.
Regarding how long does brass last? Many many facters involved in this. Talked today to one of my benchrest shooting friends. He has 5 cases with 1,500 confermed reloads in each one. cal is 6 BR, each case is bumped every 30 reloadings, normal charge is 33 gr. of 135 V/V, with a 68 gr. bullet. This is with a custom built rifle, with a precision chamber. He did state they are now ready to be retired as the primer pocket is just starting to loosen.
How many times can one reload brass, many many times.