Why? Simple. Search and find.
Search and find what? After the first draft, after the second draft, after the third draft, when you w.i.p. is almost ready to go out, then:
Search and find all those annoying words that creep into writing:
As you write, keep a list of your favorite words that you use over and over and over.
Some of my favorites are: whirled, possessed and glanced. What are yours?