Temperature sensors

[ToxicTiger]

Hi
I've been using the Digoo 433MHz temperature sensors from banggood with RFlink but the issue I have is battery life. I'm lucky to get 6 months sometimes often only 3 or 4 months. Last week I had several sensors fail with flat batteries. As I have a total of 8 sensors I seem to be for ever changing the batteries, then there's an issue where I nearly always have to re-pair the device with domoticz after changing the battery. Once up and running again they work great until next time the battery fails.
I have an ESP8266/DS18B20 which works great but it's not often easy to get power from a mains adaptor to where you want a temperature sensor.
Do you have any suggestions as to a better solution using battery powered devices, plaese?

[SweetPants]

I use Cresta Temp+Hum sensors (supported by RFLink). Battery live is several years. You can also tale a look at the MySensors project, you can build your own low power sensors.