At least every six months
To be on the safe side I would check them monthly.
Every 6 months to a year is good practice for check up and maintenance for smoke detectors.
I would say every 3 months atleast
smoke detectors should be tested Monthly
Check them every six months and replce batteries once a year, most smoke detectors need to be replaced after five years.
Once a year is a must. The last thing you need is a fire…
There is a new battery out by a company called Roost. I found it on Amazon.
It is wifi enabled so you can conn ct all of your smoke detectors and relieve alerts on your smart device. Very good idea in avoiding those annoying midnight chirps and reaching a new level of piece of mind