Hyphens, En Dashes, Em Dashes

Q. We use postdoctoral as one word. Should we then also use postbaccalaureate as one word for consistency, even though spell check wants a hyphen or space? Both are being used as adjectives.

A. Unless your spelling checker follows the same style manual you do, you should feel free to disregard it! Chicago closes up words with the prefix post-, as does Merriam-Webster.

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]