Fire departments think they are clever with their "remember to check your smoke alarm batteries when you rewind your clocks" campaign. However, I just realized that we only have one clock in our household that doesn't automatically adjust between EDT and EST. As time goes on, the campaign will become progressively less and less effective.
On the other hand, our CO alarm has one of those guaranteed-to-last-10-years battery, or so our landlord claims, so perhaps this should be a "check your smoke alarm when you replace your PC" sort of thing. :)