Logitech now has a mouse and keyboard combination that has better battery life. They keyboard goes for up to three years and the mouse goes for up to a year. I have the M310 wireless laser mouse and the batteries are six months old in it. It is my mouse at work so it is used 5 days a week for 9 hours each day.I prefer the corded mice. The cordless ones are always running low on juice. The corded logitech laser mice go for 15 euros here. By the way, mouses or mice? For the animal it's of course mice, but sounds weird for the human input device.