Hi all. I'm new to this forum. I currently own a Roland Fantom X6, Roland Juno Di, Casio WK110, and just purchased a Korg M1 (after selling a Juno 106 and Juno 60). I've been reading about battery replacement on the M1, and have read different opinions on how long the battery lasts. Some people say 4 - 5 years, some say longer, some say less. Anyone have experience on this?