Through two seasons of use I’m convinced that Dynafit bindings are a reliable high performance binding, but they’re not indestructible. It took a long time and a few reminders but Salewa USA (Dynafit’s North American distributors) were very helpful and friendly on the phone and sent me all the replacement parts and spares I needed in time to ski. As I’ve documented previously the metal post on which the heel piece mounts will fracture and break with extended use, so I’ll be periodically checking for cracks, and will carry a replacement heel post and base plate on longer and more remote trips. The plastic heel riser post can also break, though almost always the casualty of a clumsy or aggressive move (an ill-advised 3ft drop to flat while in the high climbing position broke mine). I’ll be carrying a spare with screws. Finding a lightweight Torx T10 driver for the screws was initially a challenge, but apparently Avid mountain bike disc brakes ship with a suitable driver, and my local shop (Revolution Cycles) had lots of extras lying around.
kootenayskier 
Hmm, I think I will have to drop by the bike shop this week…. Thanks for the tip.