I like to plug in my 4s whenever possible so I have enough juice when I have to go. Just wondering if the battery still use up its cycles while being charged.
In my experience, doing as you wrote doesn't hurt the batteries. Big However, you should let those batteries cycle down to at least the Low battery notification every other week. That way, you've got both scenarios covered!
In a sense, yes. It's not like "100 hours continuous plug-in = 1 full cycle" or something like that, it wears out your battery as does charge and using regularly. But yes, you should always completely drain it out to keep a healthy battery