Woken at 6 by intermittent but persistent beep. Took battery out of upstairs fire alarm, snorting at the 'long life' logo written on it. They were changed less than a year ago. Beeping continued. Climbed on chair, took battery out of downstairs fire alarm, wondering at the magic-markered 'Nov '08' written on it. Long life indeed. Beeping continued. Traced it to the kitchen and the carbon monoxide detector, with the 'replace every four years' message written on the back. Since the last time I remember it malfunctioning was 2010, I suppose it's time indeed that it was replaced. Have done so, with a unit that doesn't have batteries and doesn't have to be plugged in, and therefore can be located outside the greasy dusty kitchen. Yay hurray.
Then had breakfast, took meds, read email and blogs, lay down for a bit, and slept till 10:30.