why do we need to use city and state in our addresses if ZIP codes are already linked to the city and state?

Question

why do we need to use city and state in our addresses if ZIP codes are already linked to the city and state?

In: 100

Answer 1

This was in Canada, but about 10 years ago, I wanted to test this.

I wrote an apartment number and a postal code (that I was pretty sure was unique to that building) on an envelope and mailed it.

The US equivalent would be closer to an apartment number and zip+4.

The envelope was received. No name, street, or city.

I now live in the US, and my zip+4 maps to a portion of the floor in my building. I suspect my last name and zip+4 would be sufficient, but I’d be more comfortable with my apartment number and zip+4. But either way, it uniquely identifies my mailbox.