Some context, for people not located in the UK - A full British postcode typically aims to cover around 15 buildings (sometime a single building, sometimes a street of 50 houses). This is in contrast to many other postal code systems which cover relatively broad areas). Or to put it another way - UK - 2,643,732 codes, 1 code per 25 people, USA - 41,700 codes, 1 code per 8000 people, Germany - 8,200 codes, 1 code per…
The US also has a full 11-digit address code that is printed (by the USPS) on mail in a bar code when you mail a piece. This should take the mailpiece to a unique address.