Like you, SVL Steve, I'm in a high desert, mine that of Southern California about 100 miles inland from LA, at about 3,500' above Sea Level, and the old Albert Hammond song rules: about 6-8" of rain a year, most of that in a couple of downpours. RH outdoors is seldom over 15%, and the RH in the house is never over 35%, and during winter, forced-air heating drops it to 25-30%.
While D-man is totally right about Taylor's thin tops (truly intentional as part of what delivers their reputed sound), the trick with Taylors is that their built about 5 miles from the Pacific, where it's nice and damp and the wood is pliable. When they come inland, like up here, they
inevitably end up frustrating their owners, even those who
think they're doing enough with a case humidifier, with cracking tops. They are
that sensitive. I've seen quite a few of them like this...the ones that end up in pawn shops or at the local luthier (the guy who rebuilt my D40). We have a Taylor dealer here. He sells about 10 a year.
I subscribe to
not casing my guitars so as to not: (a) smother the wood (b) allow any chance of heat or residual humidity from a case or soundhole humidifier to buildup, leading to possible
permanent over-humidification swelling damage, and last, but not least, (c) to encourage me to grab one at will and play it.
So years ago, after nearly losing my ancient Guild D40 to this desert, its top's braces actually coming unglued on one big chord strum, leading to a $450, 3-month rehumidification and restoration, I decided it best to keep my acoustics and hollow/semi-hollow electrics in a 'humidor'. (The Colorado Rockies may have heard about it, and built one to keep their balls from getting too lively :whatever: )
I know my old friends from the WGF have seen this thing that I built - a crude, inexpensive, but effective cabinet in my den/music room's small walk-in closet. The closet's temp stays at about 68-70 degrees F, controlled by leaving the door open in winter during the day when the heat's not running and closing it in summer a/c months.
I run a little $30 cool-mist room humidifer loaded with distilled water for about an hour or so every couple of nights (I check nightly when I pull a guitar to noodle) to keep the closet's RH between 45-50%. I've got an analog hygro & thermo on top of the cab, and a Planet Waves Digital hygro/thermo thing inside it. The cabinet's bi-fold doors do not seal tightly, so air and humidity flow through under control.
Each roundhole acoustic has a Kyser Lifeguard in its soundhole (the Guild has a super-Dampit hanging inside to supplement that) and the f-hole electrics have smaller, thinner Dampit 'worms'. All of these are charged with distilled water in a weekly Saturday or Sunday ritual .
The rest of my less-sensitive guitars hang on the walls in the room (or the closet)...with dampits in the tops of the non-solids.
Since I got into this system, I
swear...I haven't had ANY of the problems mentioned here with my acoustics. And most are all solid woods. I have to keep an eye on the Guild, but I've helped her out by stringing her for Nashville tuning...all light gauge strings (only the .024 6th is wound) to keep the tension on her top at a minimum (besides giving me a great permanent use for her).
) I'll definitely be getting an "inexpensive" digital hygrometer. 
