Random cultural knowledge poll of the day, for USians. Two spaces between the state abbreviation and ZIP code:
#poll
I know the rule but think it's obsolete
12.5%
I know the rule and still follow it
26.1%
I didn't know the rule before seeing this post
61.4%
Poll ended at .

@jik

I usually put three spaces between the state code and the zip code. Or a "right justify tab." There needs to be some separation there.

By hand, I'll even write the zip code larger.