#1
I just got a new acoustic, and I'd just recently started playing around with open tunings (open D, using a capo for open E to play Police Dog Blues). I broke the G string the other day while tuning back to standard, though, and it got me wondering: I read that that kind of thing is normal when you tune the guitar like that a lot, but is there something I need to do to set the guitar to lessen the problem? Should I get it adjusted or get a heavier gauge string? I suppose I should ask at the guitar shop, but this is easier at the moment...
#2
Better quality strings will do the trick, and possibly a heavier gauge.
I suggest getting multiple guitars for multiple tunings, though.

That's what I'd do. =D
"The darkest souls are not those which choose to exist within the hell of the abyss, but those which choose to break free from the abyss and move silently among us."
#3
I've never seen definite confirmation, but I would think constantly changing tuning would be likely to weaken the strings at one point or another, especially the tuners, but I still break strings at the bridge the rare occasions they break at all so I'm not so sure...

The main reason I break strings is old, worn out or dead strings. I rarely let them go dead, but it happens now and then. Since I only have one acoustic the tuning gets changed a lot but it breaks strings no more often that the electrics do, or it seems so. At home I keep the same strings on it for 2 months sometimes, they still very rarely break and I play it for an hour or so almost every day. When they do break it's usually at the bridge I think, not the tuners. The bridge is where I beat it unmercifully...

Onstage I use different guitars for different tunings and never retune them, and I change strings every other gig on most, every gig on the ones with floating strat style bridges. In 4 years with one band in Texas I broke strings onstage no more than 2 or 3 times. One of those was of course the night I decided to forego strings on the strat...

Keep good strings on your guitar, I don't think retuning will make a big difference, unless you have a burr somewhere cutting them. I can't prove otherwise anyway and I retune the acoustic 2 or 3 times a week, sometimes twice a day if I'm working on songs in different tunings.
Hmmm...I wonder what this button does...
#4
I'll probably just try to change the strings once a month or once every 2 months, like you said. I might switch to mediums and see if it helps. The only thing I remember about mediums was that it was so difficult to play barre chords. Oh well. Thanks!