Keep your guitar wood at a relative humidity level of 45-55% to prevent cracking and/or other serious issues. But wait…are you thinking, ‘…hmmm, what is a guitar humidifier and how do I use it?’ Then watch this video of the 10 Best Guitar Humidifiers. Guitar humidity, for playing fluidity!  
Play on…
Marlene

P.S. They’re all good options, I use #3!