If you have a guitar with push-on type knobs such as the ones as used on a Fender Stratocaster or Gibson Les Paul you may experience the knobs coming loose and falling off. This quick fix is great for push-on type switch tips as used on a Fender Stratocaster and Telecaster as well. On guitars with split shaft pots you can try to sort of spread the two parts of the pot shaft with a small screwdriver. BE CAREFUL because you can snap either of the halves of the pot’s split shaft very easily. The other method is to take a small piece of masking tape and put it over the pot shaft, then press on the knob. Same remedy applies for switch tips. I saw this on an old 1950’s Guild guitar many years ago. The masking tape was yellowed with age and led me to believe that this could have been done at the factory. In any case this works very well for pesky knobs and switch tips that won’t stay put!