Guitars are tough. They're made of wood and metal that is capable of withstanding extreme temps for many years. The real key to taking care of guitars is trying to minimize the speed, or rate of temperature change. So if your guitar sits outside in extreme heat or cold, leave it in its hardshell case when you bring it in and let the temp of the instrument change slowly. Then they're fine.
I used to leave a pair of PRS Custom 24s with "10" tops and bird inlays sitting in my truck overnight, after gigs in freezing cold Montana winters. I just made sure that when I brought them in the house the next day not to take them out of their cases until several hours after bringing them in. The case acts as an insulator and slows the temp change.