Keep in mind to that some guitars are built lighter than others. The lighter ones will have a chance to move more than a heavier built guitar. Compare a Guild D55 to a Martin Authentic and I guarantee that the Martin wont like fluctuations as much as the Guild.
With all the talk about Martin binding coming loose lately, I wouldn't want to be around when the bridge and all the braces go at the same time, not to mention center seams.

Get something built like a tank. My Simon and Patrick has gone through hell and not one finish crack or hazing. Cant say the same about that custom Martin I got. Don't ask, I am not happy!!!

Apparently not! LOL.

We will leave in a few days for our northern place, and two of my three guitars, the D-18 Martin and the PM-2 Fender, both all-solid-wood, will luxuriate at home in their cases until our return in early November.

So five months time, nothing to care for them but their cases, and the A/C system, with the thermostat set for 78 degrees.

The humidity will soar outside in southwest Florida's subtropical summer heat and rains, and through most of the hurricane season. We hope the inside humidity stays under 70 as it has all winter and spring. Most of the time it reads in the low to mid 60s.

The guitars will be fine, as they were last late October when we returned.

If all fails and the A/C goes off for weeks or months, we've far more to worry about than a couple thousand dollars worth of guitars.

Just caught up with all the responses. Thanks!