I use it a lot (more than 10 hours a day, on average), at full brightness. With such use, at full brightness, I repeat, I must put it in charge every two days. As I put in charge during my hours of sleep, it is not annoying. So why did I put four stars? This is because I do not like too much hassle for nothing. All manufacturers, as well as institutional, out of greed, to discard certain services (information, demploi mode, drivers, etc.) before they provided automatically on the end user, and make the galérer -C until he discovered how to obtain it on the Internet and those who do not have internet, it has an extra shot, to add to the initial price (this price can sometimes be very high); again, this is "stealing" life time, the end user (for repetition of this practice is too widespread). for this keyboard, the illumination time default is too brief. It should be a utility, to extend it, and it's nowhere says.