Musicians don’t usually consider the value of their instrument 50 years on when they change pickups or slap stickers on it. The less a guitar has been messed with, the better. An instrument that has a few scratches on it but has all its original parts and finish is usually worth more than a perfectly refinished specimen.
The Sound Matters
Even if the body looks perfect, the guitar is no good if its sound is muddy. It should sound clear and crisp. Issues such as fret buzzing may be significant or minor depending on their cause. If the neck is severely warped, that will usually seriously diminish the guitar’s value. On the other hand, if a little set up work will cure buzzes and tuning issues, the impact on value is negligible. A guitar tech should be consulted if you’re not comfortable with setting up a guitar.
Materials Are King
Due to their endangered status and scarcity, certain prized tonewoods such as Brazilian rosewood are no longer used to build guitars. The same is true for tortoiseshell, ivory, and ebony inlays and embellishments. Their presence signifies a quality instrument and will usually positively impact the guitar’s value.