I know this is a dumb question. How often do the trip mileage knob works it way loose? I lost mine a week ago. I replaced it, and put lock tight on the screw. Mainly, I was wondering if I should keep a spare on hand if this is normal. Thanks for your answers.

I have learned to keep at least two of everything for the bike, sounds like you should not have a problem, the lock tight red or blue should hold that knob there. I pretty much check all the major bolts before I ride, sounds anal but I like to ride with a safe sense of mind and it only takes the time it take for the bike to warm up.