I have several liner locks , like many of you.
I have not had a single one fail from being used too much but , then again I switch my EDC pretty much bi-weekly.
I think one would have to use their single liner lock knife consistently for a several years before the liner became weak from use.
Value ? Well if you paid $500 for a liner lock of exotic materials and fancy brand name , and the lock became weak then of course it would go down in value, that is depending on how bad someone wants it , how rare it is , was it a custom , and so on.
I think of the 'life' like this , I have several old clips for my Colt Woodsman 22 , the springs still have plenty of life in them and the clips are at least as old as me.
As long as the liner is not made of pigiron , you should be good.
IMO