change your clocks, change your battery

Why the campaign to change your smoke alarm batteries every 6 months? Who's paying for this, the Eveready Corporation?
Batteries are toxic and shouldn't be dumped into the landfills, but you know most people do. It's bad enough to have dead batteries as toxic waste, but millions of perfectly good batteries tossed every 6 months? That's just wrong.
Smoke alarms beep when the battery needs changing. Wait for that cue, people.