Alarm Batteries

They work well when I put new batteries, but a month later they start chirping again. These batteries are expensive and I wonder if I need to buy new smoke alarms in place.

Because the batteries are good (not the 29 percent) of the cost of a smoke detector new sentence. Get a good brand too!
I have a pair of brand Kidde smoke more carbon monoxide detection devices and you should have to change batteries once a year (in October - Month of the Fire). I cheat and leave for 2 years [the] Duracell.
Good luck! ! !

Buy Duracell or Rayovac and it will go for one year. Nothing worse than the smoke alarm chirps.

Good Luck

The life of a smoke detector is about 10 years. So if yours are becoming around this age, they are probably due to be replaced. But if they are a year or so old, then back to where you have purchased and they should be replaced for free. Using a fast battery is not correct.