Originally Posted by: da_beaverwhat do you mean? trying different tunings on the same guitar is bad?

sort of.. it's just that a guitar has so many checks and balances, everything is balanced out, the truss rod has to pull against the tension of the strings to keep the neck straight, the trem has to counter-act the pull of the strings in order to stay in a "floating" position. etc. etc. so when you loosen the tensions of the strings by detuning it, you send all these balances out of whack. it won't necessarily break your guitar unless you do something extreme (let's say, for example, you decide you want to tune the guitar up two whole steps. that's insane, the tension will probably snap the strings, and if not, it'll pull the bridge right out of the body, or the tuners out of the headstock, or even break the neck. now, obviously, that's an extreme, you wouldn't do something like that)

detuning to C won't break your guitar, but it will throw the balances out of whack, and your guitar won't perform at it's best. if you're really serious about having a guitar in C, permanently, you should have it set-up in C by a tech, who will adjust all the balances of the guitar, so that it does perform at it's best when it's in C. if not, then don't worry about it too much, but switching back and forth between standard and C could throw the balances even more out of whack, and in turn could endanger your truss rod. (just for your reference, because I don't know if you are quite sure what a truss rod is, but even if you did break a truss rod, it's not the end of your guitar forever, you can have a new one put in, but it probably won't be cheap to do so.