The Comp tip derives most of its stiffness from the fiberglass reinforcement. The stiffness of glass does not change over time. As such, the stiffness of the comp tip should not change with time.
Unfortunately for some, the strength may change with time, due to impacts, ice, fatigue, sun, heat... All of these things can change the strength of the comp tip without changing the stiffness.
There are other factors that may impact both the strength and stiffness of your comp tip, like uneven wall thickness:
https://www.hobie.com/forums/viewtopic. ... ss#p279043Generally speaking the processes that may impact a materials strength (work hardening, aging, tempering) do not impact it's stiffness. The exception would be polymers, where anything goes and there are no rules.