Regarding battery lifecycle, Panasonic has an "Economy mode" on their Toughbooks to extend the number of charge cycles that a battery can go through during its life. While in Eco mode, Toughbooks will only charge to 80% of the battery capacity. In their lab testing, a battery in Eco mode will achieve 50% more cycles before wear and tear reduces battery capacity to half of spec.

See the bottom of this page http://panasonic.co.jp/pavc/global/t..._battery_life/

Panasonic is one of the major innovators and manufacturers of Li-ion batteries, and I would trust their research.