A widow friend of the family asked me to clean & check the two handguns she had for self-defense- a Glock 42, & a Model 15 that belonged to her late husband. Neither were functional.
The Glock 42 has never been cleaned or lubricated, and had frozen shut. I eventually got it to open, and found that it wasn't even loaded. Had she tried to use it, she would have had a really bad time.
The S&W's cylinder rod had backed out, so it too wouldn't function.