IME you can maintain gear very well and still have a specific component or components fail from normal use. Some things just plain wear out or fail due to some manufacturing flaw. I've had a stop fail on a pot that wasn't forced beyond the stop. I've had switches and jacks malfunction where pressing on a tab to improve the contact still didn't fix the issue. $hit happens or there would be little need for replacement parts. FWIW I've also had shoes wear out just from walking in them and clothes wear out just from wearing them. DeOxit didn't repair them either. Not trying to be a contrary bastiche but Duct Tape and DeOxit can't fix everything that breaks.