What are the symptoms of low quality guitar machine heads? I know it can be the nut that's causing the problem, but besides that, how can I know whether changing the machine heads will help my guitar stay in tune longer?
In my particular case, they seem to be O.K. but I am not sure. They feel just a little bit loose while tuning the guitar (compared to the other more expensive guitar I have), but I am unsure if something changes while playing or is it just the nut. Btw., the nut was changed once already some time ago because I wanted to put thicker strings and it did make a huge difference.