What is considered a serious drain... amongst others, I have a 505, with a 16GB SDHC card, that I recharge around every week to ten days. It is never switched off, only put in standby and I read at least two hours per day, up to six on a lazy day. As this means (worst case) 52 charges per year and this battery type (depending on your source) is good for 400-1000 charges that works out at around 8-20 years of use... if the rest lasts that long, I'd be really happy...