I've found a notable difference in battery life (both overall longevity and each session length) based on whether I plug the device into the PC for charging via USB or I take out the batteries and use a purpose-built charger. With the mouse, which uses up battery life fastest, it is fairly simple, and it means I always have one ready to go, so I can crank up report speeds without worrying about making it to the end of a gaming session. Unfortunately, it is a PITA on my keyboard, so I usually just charge via USB, and only pull those batteries for a proper charge on occasion.