Consider a spring like this (this one CoC hand gripper):
They claim on their web site, that the spring will not degrade during time:
Do your grippers get weaker with time? No, so don’t worry if your Captains of Crush No. 1 gripper is feeling easier to you now—it’s because you’re getting stronger! What is mistakenly called “seasoning” by some people is actually a weakening with use, and it’s a reflection of an under-designed gripper with a spring that is bending, which is why it’s not uncommon for low-quality grippers to get narrower and easier as they are used. On the other hand, Captains of Crush grippers hold their line for a lifetime of steady training.
There is also a lot of discussion on this topic, referencing some re-measurements, but none of that seems really trustable.
My questions, from engineering point of view:
Is that possible/probable? I mean, can the degradation be small enough (for the given brand) so the user should not care? How likely it is true?
Is possible what they say about the "low-quality grippers" that they degrade over time significantly. How probable is that?
I can imagine that both options (degradable and also stable springs) are possible. But how probable it is. Note that such a product cost usally $10-25.
I know this is kind of opinion based question, however the experiment would take few years, so any theory and/or experience based answer can help.