The H9 switches are pretty solid (we have had little trouble from them). Since they are real complete switches, connected by wire to the circuit board, they would not be too hard to replace. But, they are getting harder to find, so we may have to use a different part in the future.
Clearly, if you were to only control it with MIDI, the switches would last for ever, but then you would have to worry about the switches on your controller. Can't win !