I only have one cheap electric guitar. I go back and forth with the tunings alot, from standard to drop d,c, and b.

I was just wondering if changing the tuning all the time puts any extra wear on the strings? I'm always afraid they're going to break. I've had them break before, just wondering if changing tunings often, reduces string life?
well i think it does, but i dont worry about that.

i have an old guitar that is constantly going between drop A and standard tuning and the strings have lasted a while.

However if you are looking for a reason to get a new guitar, new tunings could be you reason
what gauge strings are you using?
yerp im sure ill add something amazing here some day.
So you use the same gauge strings for standard and drop B?

The rattle on that must be pretty epic
yea i think it does put some strain on them..but like said before nothing you can do unless you wanna capo it and i dont think you wanna do that...u just gota live with it...

i have three guitars ,keep the lespaul in standard drop d my peavey tele in halfstep and a strat copy in fullstep drop so i can play anything from senses fail to brand new to killswitch engage
I don't see how it would increase the stress put on the strings, unless you tune it to F# or something.

If anything, switching to and from lower tunings would decrease the stress put on them. Think about it.
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Tuning up = broken strings.
Tuning down = crappy sound.

You don't put any stress on strings when you tune them downwards, you're just going to have them rattle like crazy. Also changing tunings like that must be hell on your intonation.
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It might wear them a little bit, but I wouldn't worry too much about it. Changing strings isn't a bitch unless you have a floating trem.

BTW I've broken a nut on a tele but never a string. WTF =(
On this subject, what would be a good string gauge to use for standard E tuning where I can tune down to maybe drop C or so without the strings being too slack? Or in other words, what would be the heaviest gauge strings you would use in standard tuning, with regards to string and neck tension?

I just want to be able to drop tune every so often, with a decent enough tension in the strings, but not use a gauge so heavy that when I am in standard I can't bend notes etc.