You shouldn't have to replace pistons every year, huge waste of money.

What you should do is check compression after your rebuild. Once broken in, check compression again. Keep a notebook of these notes.
Check compression once a month or every other month. Record data. If it stays the same or less than a couple psi drop, i wouldn't worry about it till it is 10-15% less than original broken in psi. Even then, usually new rings and hone (if piston to wall clearance is good) will work. Shouldn't have to worry about piston till you need to bored it out.