The number of spaces that follow an abbr. is one.
no spaces
2
2
1
50 million gazillion
Unlike the period at the end of a sentence (which have one or two spaces), the period following an abbreviation only needs one space. This is the general rule for abbreviations such as Dr., Jr., or Sr.
There aren't any spaces after the apostrophe in a contraction (did you see what I did?)
None!
none
There should be one space.
The city, ST ZIP line should be punctuated as follows: City, ST 12345 Name of city followed by a comma and one space. Then 2-letter state abbreviation followed by 2 spaces before the ZIP code.
One space is sufficient.