Hello Jon,
Your suggestion to use the different keys of the car on a regular basis is not that bad.
Theoretically the control units should always 'remember' the latest roll code but it is not too bad to have the keys used now and then, not only for the remote control function of the door locking mechanism but also for the transponder function which is served by a separate chip in the keyhead. Some/most of the drivers (at least I think so) put their 3rd small spare key (without remote control) somewhere on a 'secret' and hard to find place somewhere at the outside of the car in case they loose their original key when they are underway. If you need this key e.g. after 2 years then the transponder chip will do its work.
To come back to the original topic I however must admit that even after one year not being used the door lock remote control should be recognised by the control unit. However it quite often happens that the 'spare key' is not serviced in time and that the key battery goes flat and then the circle is round and we come to the comment I gave in my previous comment in this issue.
I am quite anxious to learn how JB's story will end...
Regards,
Alfred
