Matty, you should not have to re-register a phone each time, but you DO need to manually select which phone is actively paired via the Audio unit in the Kluger. Doubly annoying is the fact that this can't be done while the car is moving. To select which phone it chooses to pair with (from memory, so I hope this is right!), press the Green off-hook button, rotate the left Audio button to select Bluetooth and then press, rotate to Select phone and press, rotate and press to select either yours or your wife's phone. IMO this is very poor design by the audio system manufacturer - my Mits Triton with cheap factory Bluetooth will choose whatever phone is in the car at the time! Hope that helps