How do they construct a building next to another without any space in between?

When shops or houses are built completely adjoining—that is, with exterior walls abutting (but not sharing interior walls)—how is the construction process managed? How is it different from building a free-standing structure?

I’m thinking particularly of cases where they are not all built at the same time. (Or are they?)

Examples:

shops
houses

And what happens if one of the buildings is taken down? Do its former neighbors need new exterior sides?