It's worth noting that the K810 is rechargeable, however. You can leave it plugged in over USB while it's at your desk, and unplug as needed. I carry mine around with a tablet as a laptop replacement and charge both every few days. I can handle 2 or 3 days of life if it means I don't need to stock AA batteries.
Yes, actually I like the idea of an internal chargeable battery through USB much more than replaceable AA batteries, since nowadays I´m very likely to have one (or two) USB chargers around when I´m travelling.
