Back to the topic...
Covers & Microfiber inserts - only really need one wash to get any residue/chemicals off.
"Organics", cotton, bamboo, hemp - may need five or more washes and dries to get to full absorbancy. You won't want to wash any microfiber in with these the first time, as the oils that come off of the cotton can sometimes cause the microfiber to repel.
i didnt know that either, oops