I am a stickler for detail and perfection. One thing I hate is when I am at a field and a gun breaks, only to get home and find the issue was preventable. 

Late last year my Tokyo Marui NGRS AK-47 stopped working on a day I was using it as my primary. I could not make time for a field repair and instead had to use an LMG. After getting home, I checked the gun only to find that the issue was the selector switch screw was loose and when I out into semi or full auto it was not turning the actual spigot inside the gun. Had I done my usual monthly maintenance, I would have noticed the screw was loose and not think my trigger was broken.

Lesson learnt and now I do not skip maintenance day!