Buying an Acoustic Guitar
If buying an acoustic guitar you need to check a few other areas to ensure you don't end up with a turkey!
Check that the bridge saddles are present and not worn out, that all bridge pins are present and no unbroken pins are stuck in the pin holes. Also ensure the bridge is not lifting from the body of the guitar.
Check there is not a significant amount of bowing of the top of the body of the guitar by sighting across the guitar body.
If the guitar has a piezoelectric system installed, plug it into a PA or amplifier to ensure the electrics are working.
And importantly, just remember that the better quality acoustic guitars (and obviously this also goes for electric guitars) will have a higher resale or trade-in value when you come to eventually changing it (as we all do!).
Back from - Buying an Acoustic Guitar
Buying a Guitar - Part 2
Buying an Electric Guitar