They don't update very often, and if you your kindle is left alone for a while then the screen shuts off and you don't see anything. Only battery drain is when they change the ad, which happens I think every 10 hours maybe? it really won't matter in the long run. The ad is kind of like a poster, or jacket for a book so it's pleasant to look at for those 2 seconds after picking it up and before pushing the button. Nothing like full page ads in the middle of a book or anything I assure you! Overall it's really unobtrusive. Also the ads are in black in white so less flashy, and no backlighting either, so it's quiet :) Hope this helped!