How do you manage battery health of your development devices when is always plugged in?

I know this question is not programming related, so for this I made community wiki. Developers are the best guys to answer the question.

I am addressed to those that do development on devices that runs on batteries, like phones, gadgets etc. Probably you are constantly develop for them, and therefor they are always plugged in and charged at 100%. We develop mainly for smartphones and we have devices that were always above 90% charged in the last month or so.

If a battery is always charged, it degrades it life cycle, so what steps you do to ensure decent battery drain to maximize the life of the batteries.

1. Keep it unplugged sometimes. For a laptop, you can use the laptops battery just fine. For a mobile device like a phone, this is a little more annoying because you are trying to upload to it fairly regularly (but not constantly).
2. Use the spare. Have a 'dev' battery that you use when constantly plugged in. When done developing and ready to show off your new fart widget to all your friends, just swap the battery out.