And now that I'm thinking about it, I realise that I just tossed them in the rubbish without giving it a second thought. Please don't do that; go to this site, put in your location, and get a list of drop-off spots for all kinds of batteries.
We've had to buy a second set, of course, but that's all we've bought in five years. They are saving us money, keeping dead batteries out of landfills or recycling centers, and keeping new batteries from having to be made (and the metals and chemicals thus required are doing whatever it is metal and chemicals do when they aren't in use). Does it make much of a difference if it's just us doing it? Not really. The good news is that it's not just us doing it. Which is the sort of enviro-thinking that keeps me going when I see litter on the side of the road.
Do you use rechargeable batteries? Have you found some long-lasting ones? Have you ever recycled your batteries?