Everyday vs. every day

I saw this sign, of course, outside of a laundromat.
















For those who are confused by this:

• "Everyday" is an adjective. It describes a noun.
  Example: My everyday routine is boring
  
  
• "Every day" is an adverb. It describes how something is done.
  Example: Laundry opens at 6:00 a.m. and closes at 9:30 p.m. every day.

Hint: If you can add the word "single" to "every day," as in "every single day," then you know it needs to be two words, not one.