I have also have an older 555 in 440C along with a Mini Ritter. Both have seen several years of EDC, In fact unfortunately during that period both eventually had the tip chipped. For both knives it was a random fall out of my pocket as something like a shirt tail caught the clip and lifted it out of the pocket. So I re-profiled both by hand and they are still great EDCs.
But with the time, wear and tare the price I would sell them for is lower than the value left in the knives for me as users.
Don't know if I explained it clear enough.