Overnight or anything similar to that is perfectly fine and won't damage the battery.
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266 in half a year sounds like a fair bit. Shouldn't be enough to degrade the battery much, but still more than it should be in half a year. So was this a brand new phone originally?
Yup .. that is a LOT for 180 days of use ... must be 90 or so 20 hour days of talking there.
Battery Doctor (Free App at iTunes) recommends you charge when the battery is less then 100% and greater then 20% ... seems making your battery exhausted with a complete drain might not be such a good idea.
I downloaded iBackupbot .. and that is a great application for iTunes data.
Real nice to have ...
Big 'Attaboy' to the code hackers on that one.
Oh ... I just charge on the USB chain off the iMac ... powers it up in about an hour of noodling around the internet, checking the weather, road conditions, pending news, email, sync to backup ... etc.
Alan