I thought I had won my own personal lottery.  The smoke/carbon monoxide detector started beeping a week and a half ago -- but not at 2am.  It was a relatively reasonable hour with the exception that it was the only day I get to lay in bed longer.  By the time I had the dog out and came back upstairs to figure out which one it was it had stopped.  A couple of days later it started again -- this time at 9am on a work day, even better.  I changed out the batteries, counted my blessings that it wasn't beeping in the middle of the night and went about my day.

Here we are on Friday after this started and it's beeping again.  The batteries are good, I know it.  So I look it up.  Every 30 seconds beep means that it is nearing end of life (rather than 1 beep every 60 seconds).  Lesson learned.  But in the mean time, it won't stop beeping - and while I keep plenty of batteries here to avoid this annoyance I do not keep extra smoke detectors.

I certainly hope that the same brand still uses the same connectors and should be an easy swap, but until I see it I'm not going to expect it.  My first thought was, should one just replace all of them at once?  I mean they're all 10 years old.  Then I saw the price of one.  Ouch.  It's discontinued hence the high price.  The replacement they point you to?  It has a different connection, so I'd need to swap out the connector to the hardwires.  Keep in mind I still have one arm that doesn't go up, hence I haven't change the light fixture over the sink in the basement yet.  Good times.