ernie ball rusts too fast. I didn't touch one of my guitar for a week and the strings started rusting. Cause at that time i was experimenting with strings. I still think that Dean Markley are the best la. And for acoustics, i use GHS *something* bronze. I know it's the red one at yamaha. Once, i didn't change my strings for at least 5-6 months, they still didn't rust. Actually, depends if your house is very humid la. If humid, use thirsty hippo. But don't put everyday cause if the wood is too dry, it may crack.