For what it's worth, I've been playing for years, and I own a Breedlove acoustic that I've done simple maintenance on such as cleaning the exterior and replacing the strings. I used to keep it in its case (soft shell) but for years I just leave it propped up on a wall next to the radiator when it's not on. In the winter I move it to a wall without radiators. Hasn't seemed to damage it at all. On the other hand, I would never leave it in my car on a cold winter night or during the summer heat. It's really up to you since your guitar is a new purchase, and I'm sure you want to protect it, which is the right thing to do. I would say keeping it in its case would keep it safe and playable. You'll of course find people who swear by using humidity packs, but I'm not one of them. I wouldn't take advice from a guitar sales store b/c they would probably want to sell the packs to make a sale. Do you know any experienced guitarists you can talk to about it, those who do not have a stake in selling you something?