@jernej__s @PeterLudemann @ashwin @Dav

Address boxes annoy me so much. In the UK, every postal address can be identified by two pieces of information:

The building name / number.
The postcode.

In any situation where this is not the case, the Royal Mail subdivides the postcode to make it true.

If you're building a system that accepts international addresses, you need to support a load of different things, but there are a bunch of forms I've filled in where they only accept UK addresses but make something like city or county mandatory.

@david_chisnall @jernej__s @ashwin @Dav
The Canadian postal code system (modelled on the UK system, enhanced to make typos difficult) can distinguish individual floors within a single building. The 9-digit US zip codes can probably do this also, but everybody uses the 5-digit version (the Canadian ones are all of the form V0R 2G0, with the only special encoding being that "0" in the 2nd position means it's a PO box).

[BTW, for a while I lived in Japan with an identical address for about a dozen houses; the only way to distinguish them was by the name of the addressee]