A quality instrument is made of wood, an organic material that reacts to the environment- specifically humidity.
Ideal conditions for the guitar range from 40%-60% relative humidity and comfortable room temperature. If the guitar is exposed to very dry conditions ( lower than 40% r.h.) then we risk cracks on the top/back. On the other extreme, high humidity ( >75% r.h.) will cause swelling and distortion to the top, and begin to deteriorate the glue joints.
Use common sense and avoid extreme conditions. When you are not playing, keep your instrument inside its case in a comfortable setting. Never leave your guitar in your car/trunk on a sunny day, it can cook. Do not leave your guitar in direct sunlight (next to a window) even if its in the case, or next to AC/heaters (they dry the air).
If you live in a place with extreme conditions, please discuss it with me and I will advice you on the best way to take care of it.