One of the features that TextExpander offers is the ability to nest snippets inside of one another. This has a lot of applications, but one of the handiest is the ability to separate commonly-used sections of snippets that are subject to change. Doing so allows you to update a single snippet and have all other snippets that reference that information update automatically.
This is a companion discussion topic for the original entry at https://brettterpstra.com/2014/08/05/save-even-more-time-with-textexpander-snippet-nesting