Not your everyday update

I slipped. I overlooked this wonderful entry on the "every day/everyday" error from 1999's Sleeping Dogs Don't Lay: Practical Advice for the Grammatically Challenged, by Richard Lederer and Richard Dowis:

"I will always speak my mind. Every day," says a man in a Toyota TV commercial. The screen turns black, and the slogan materializes: TOYOTA/EVERYDAY.

The Toyota people goofed. Every day styled as two words, is an adverb that means just what it says, as in "Every day in every way we get better and better." Everyday, squished together as one word, is an adjective meaning "commonplace, ordinary," as in, "an everyday occurrence." Did the Toyota hucksters really want to say that their products are commonplace and ordinary? We don't think so.

When you mean "all days," write every day, not everyday.

(Cross-posted to The Anger of Compassion)