month life expectancy at best [SEP] bought two one in june the other in october of the one purchased in june died right before the october purchase return window closed so i bought another thinking it was a fluke it wasn t seems they last about months and that s it i m sure it ll last even less for someone that isn t using it just once or twice a week for hobby paint about the same size as a nail polish bottle the battery option is also useless even when they re new the batteries barely shake it at all you re better off just holding the paint with your teeth and sitting on a vibrator