What is the life span of a phono cartridge?

I have recently just gotten back into analog, having purchased a Basis 1400, with a RB 300 arm, and a NEW Benz Micro Glider II cartridge. (It sounds very nice, although I realise it is not the ultimate in analog, but it is at least one step above entry level).

I assume the life span is at least a few hundred hours, but is that 300 or 900? Also, how long before the cartridge starts to degrade? What are the first signs that the cartridge is starting to go?

Any help or thoughts you have would be appreciated.

Thanks!!