Greg, if you read any Tarantino scripts or James Cameron, they have plenty of typos. Of course, they are writer-directors, so they don’t care. While most scripts written by pro writers are almost error free in terms of typos and grammar, you’d be surprised how many are not.

That said, you want to write as “clean” a script as possible. Don’t give a script reader or development exec any excuse to drop out of your story universe once you’ve lured them in.