#1
i only have one acoustic, which i use between three or four tunings. standard, DADGAd. open G, and open E... drop d occasionally for one song.
its usually in standard though.
i only tune to other tunings for a few songs.
i had just got done playing She Talks To Angels(black crowes)[open E] and messing around in the different tuning, trying to write something in it.
i got bored/ frustrated with it and started tuning back to standard... and my G string snapped!
i was using Ernie Ball Earthwoods , lights
i had bought these strings before and the same thing happened, tuning back to standard from open E. i was using a different gauge then. they were "Rock and Blues"
but i dont think they were much different from the lights

i bought them because i was tight on cash the first time.
the second time i bought them was because they were cheap and their package smelled good. it smells like oatmeal or something(why)?

i dont tune to different tunings very often. i usually tune to Open E, maybe once a week. same with the other tunings
so i dont really think that this was the problem, they were less than a week old.
i dont live near a music store, the nearest is about 2 hours away. so now i cant play my acoustic till next time i make a trip to boise.

what are some good acoustic strings that dont break easily for around 10 bucks?
#2
I got ernie balls stainless steels on my acoustic at the moment and they don't break as easily as the earthwoods. I tuned my whole acoustic guitar half a step down with the earthwoods and when i tuned back up one of the strings broke. Daddario strings would also be a good choice.
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