Sometimes, I get a burst of insight at the most peculiar times ... like after I get home from a long night downtown.
Chirp ... chirp ... two minutes doesn't seem like a long time, unless it's the amount of time between beeps that your smoke alarm uses to tell you to change the battery. So I do my usual: stand in the hall facing the detector there. It's either straight ahead (hallway), left (computer room), or right (extra room). Of course, it's the extra room.
Funny, I just changed that a few months ago. So why is it that one and not the other two?
I get up on the stepladder with the light off, because I can see from the light in my hall. (Apparently Arbor Homes screwed up the wiring in the third bedroom: it's opposite the lighting in the laundry room, hallway, and second bedroom. Turn the switch on in the third room and the others turn off. This is why they didn't install a fixture in that bedroom, so I wouldn't notice.)
Hey, wait a minute. If the lights are off ... what if the wiring for the smoke detector is messed up too, and so it's always running on battery power, so it drains the battery faster?
Now, that may not be the case ... but it sure is a coincidence.