Striped and patterned pillows and blanket on bed

The question: How often should I clean my pillow?

The answer: Every three weeks for the outer cover, and every three months for the pillow itself.

The concern is less about the pillow breaking down and more about the host of critters and debris that can be found in the pillow you lay your face on night after night. Dirt, oil and dead skin cells get trapped there, which may lead to acne. Dust mites, which belong to the spider family, also like to hang out in the crevices of your pillow. "You can't see them, but they're concentrated in things like bedding and carpeting," says Mark R. Neustrom, DO, of Kansas City Allergy and Asthma Associates.

Dust mite accumulation can cause very real health problems, namely unpleasant reactions in people who are allergic to the bugs. Neustrom says that of all people with allergies, around two thirds of them may be allergic to the types of dust mites that congregate indoors.

And unlike allergens like cat dander, the protein that triggers reactions to dust mites isn't typically airborne, he says, so symptoms that are particularly strong first thing in the morning is a good sign the problem might be your pillow. Anyone with year-round nasal symptoms also might want to get tested for a dust mite allergy, he says.

So buy a cover for your pillow, and clean both items frequently.

Zippered pillow protectors certainly help mite and buildup woes, as can washing pillows regularly. Interior design expert Robin Wilson recommends washing your pillow cover every three weeks in the washing machine. Then, wash the pillow itself every three months: Down-alternative pillows can go in the washing machine, while down feather pillows should be dry cleaned. Thirty minutes on low in the dryer can help clear out some of the clutter from your pillows between cleanings, says Robert Oexman, DC, director of the Sleep to Live Institute.