The technology is really mature well. Certainly the reasons is that a day automatically recalibrated once the smoke detector! Ie aging of the electronics (yes, there really is such a thing), clouding of the optical unit, such as dust deposits and deterioration of battery voltage are automatically considered. The response is still sensitive enough.
Networking via radio works perfectly well. The battery life of 2 years, I can confirm.
I can only recommend the detector.
Optional for securing ideal Magnetolink.