Expert advice on washing and replacing pillows

When was the last time you bought a new pillow? Can you recall when you last washed the pillows you (and your family) spend a third of your time sleeping on? If you're like many people, you probably don't give it much thought.

Yet even the most basic pillow maintenance can have a positive impact on your health (and how well you sleep). Most pillows are loaded with dust mites, which can trigger asthma and allergies. Dust mite byproducts build up in pillows over time. The older your pillow, the more dust mites it contains, the worse your symptoms can get.

And even if you don't have allergies or asthma, who wants to sleep on pillows infested with dust, dirt, and more? Luckily, there are some simple steps you can take to make sure you're sleeping on the healthiest pillows possible.

Wash pillows regularly

• Robin Wilson, an eco-friendly lifestyle expert, recommends washing pillows at least every three months. She makes a good point: "Would you wear your pajamas for three months without washing them?"

• Most pillows are machine washable, but check the labels before tossing them into your machine. Older feather pillows may require dry cleaning. Use the delicate cycle. Check seams on down pillows so that feathers don't leak out. Wash pillows in pairs to keep your machine balanced and give them an extra rinse.

• Pillows can go in the dryer on a low setting. Fluff often. Throw in a couple of unused tennis balls and dry thoroughly.

Add an extra layer of protection

• Encase each pillow in a zippered allergy proof cover and place a pillowcase on top of it. Wash pillow covers and pillowcases with other bedding in hot water (130 degrees F or 55 degrees C) once a week. Cold water will not kill dust mites.

Replace old pillows

• Wilson suggests replacing your pillows every three years. A new pillow that weighs 10 ounces can double its weight in three years, according to Wilson. Those extra ten ounces are dust mite remains, she says. Washing your pillow will help, but it's still a good idea to start fresh every three years.

• If you have asthma or allergies, buy hypoallergenic pillows, which are typically foam. Otherwise, feather pillows are fine, but make sure they're machine-washable so you don't have to get them professionally cleaned. Check out these buying tips from Martha Stewart.

• Used pillows make great beds for pets. Take your castaways to your local vet or animal shelter.