Last night relative humidity at Château X-Rated hit 20%. That's low. That's dry. This morning it's sitting at 26% which is still on the dry side.
So this can pose problems for guitars. It can also mean that you're convinced that something untoward has happened to your guitar and it needs attention from a technician, but all it really needs is humidifying (I've been through this, the technician was an honest man and told me what to do).
For acoustics symptoms may include low action, string buzz, the top appearing concave, protruding frets and, in extreme cases, the top and sides separating, the top or back cracking or the bridge lifting.
For electrics it's not as bad, but you may still find the neck or fingerboard shrinking and thus the frets protruding or possibly the action changing.
Solid wood acoustics will be more prone to problems with humidity than guitars made from laminates.
See
this note (originally from Larrivee) for more details. Keep your guitars in their cases. Yes, they do look pretty on the wall, but the case serves as a buffer (but not total protection) against damage due to humidity.
If your guitar suddenly starts misbehaving, consider that it may be a humidity issue (usually reversible) before rushing off to a technician or having a go yourself.
