Q: Since winter is so dry, I want to make sure to humidify my guitars. Do I only need to worry about acoustics, or are solidbody electrics at risk, too?
A: Electric guitars dry out, too…and wooden tables, chair legs, wood trim, etc. With solidbodies, drying out usually manifests in warped necks, but unfinished fingerboards (rosewood, ebony), etc., dry out, too. You may even notice the tone of the instrument changes.
Acoustic guitars are more susceptible to cracking, especially those with solid woods for the top, back, and sides. Acoustic guitar tone and sustain can definitely change in addition to the danger of structural damage to the instrument from dry conditions.
Try to keep the humidity in the areas where your instruments are stored around 40-50%. It is also best to keep sensitive instruments in their cases.
A wide range of products are available to help maintain proper humidity levels for guitars and other wooden instruments.