Permanent battery smoke alarms here. No wiring no battery replacements. Best of both worlds I think.
This is off topic, but a worthy subject to be discussed in this thread as it reminds people to replace their batteries in smoke alarms.
The interesting part about Lithium powered smoke alarms is that one is unable to comply with the local bylaws that state that battery powered smoke alarms are required to have new batteries installed once a year. (note the Victoria bylaw was written in 1992 when David Turner was mayor) I am unsure how a judge would view potential negligence should a rooming house burn to the ground and there was no "record" of replacing batteries annually. There are a LOT of older converted buildings out there that are used as multi occupancy, and it was cheaper to install a battery powered smoke alarm than fish in a 120 volt feed. Our bylaws need to be reviewed from time to time to reflect ever changing technologies.
One must also be careful with the newer smoke alarms (either battery or 120 volt) that contain dual technologies that include the detection of carbon monoxide. Some of these devices need to be replaced with new every 5 years.