What your friends tell you about battery conditioning probably does not apply to the Lithium-ion-polymer batteries presently used by most computer manufacturers.

This is what you need to know.

1. It is OK to keep your laptop plugged in all the time.
2. You run your laptop on battery at least once a month – this should be easy, it’s a laptop right?.
3. Battery capacity diminishes over time. Expect to lose most of the capacity within 2-3 years after manufacture.

via post by Laptop battery myths

Battery technology has unfortunately not caught up with the rest of technology. Laptops with batteries that lasts for days are long overdue.