That’s depending on so much parameters, I think it’s nothing merely a best guess:
- how many key turns you use
- do you only use Nuki - even if the lock isn’t closed to open the latch every time you open
- how often you use it anyways
- how “easy” the key moves in the lock
- how far away either the BT-bridge/ESP32 or the WiFi Router/Repeater is
- which batteries are used (“normal” AAs or the Nuki-built LiIon block)
my Nuki3-lock (BT-only) with Nuki battery block lasted around max 2months (promised was one year) until I changed from the bridge to the ESP32-NukiHub in december - you can see the extremely more flattened curve since:
