Quality acoustic guitars are made from solid wood. It is essential to maintain a proper moisture level to prevent adverse effects such as bad string action and buzzing, protruding fret ends, cracking, top-sinking, and other damage to your instrument. As always, your case provides essential protection from drying and other environmental effects, but in areas prone to severe dryness and/or cold, (such as heated homes) you MUST use a guitar humidifying device.
There are several stringed instrument humidifiers on the market that are specifically designed to maintain or restore the proper moisture level. These include the clay-filled type (about the size of a small film canister); the vinyl soundhole-cover type; and the long, "rubber-tube" type, which is the type we recommend, although we do sell all three versions.
Of the tube types, we recommend the larger one, which is approximately one foot in length and 3/4 of an inch in diameter. The "film canister" type humidifier releases moisture in discreet amounts and only works well in areas of minimal dryness. The vinyl soundhole cover types work well enough, although they have a tendency to trap the majority of the moisture in the body, not releasing enough into the case to benefit the neck.
The tube humidifier often comes with a plastic soundhole cover containing a humidity gauge. To make this humidifier more "user-friendly", discard the plastic cover and use only the tube itself. Like most humidifiers, the tube type is basically an encased sponge. Hold the tube under cool tap water, until the sponge inside is saturated. Then wring out the last drop of excess water, and dry off the outside of the tube. This is important, because water drippings can damage your instrument. Suspend the tube inside the guitar body by wedging it between the G and D strings, so that the plastic cap prevents it from falling into the guitar. This enables the moisture in the tube to humidify the body, the neck, and the case.
How often should I Re-Wet the humidifier?
That depends on the season and the region in which you live. As a general rule: