I am not sure if this has been mentioned and I am not sure where I saw it. If you are still using a digital camera for some shops, like me, remove the batteries any time you are not actually using the camera. I kid you not, the batteries end up lasting at least 10 times longer. I still use the camera for certain shops that require a certain resolution and do not require a date an time stamp, so I never have to reset the date when I put the batteries back in.
I have also started doing this with the flashlight I keep in the kitchen drawer for emergencies, and I am still using the same batteries from four years ago.