I am in the market for a new pillow. The one I am currently using is almost six years old, and I think it has already served its purpose. It's so limp and out-of-shape and has already survived several rounds of washing, it's time to look for a replacement.

A common belief is that pillows made of synthetic fibers such as polyester and polyurethane are better than down or feather, in terms of non- or hypo-allergenic properties. But some say it isn't so.

According to Dr. Ashley Woodcock, who led a study recently at the University of Manchester in England, synthetic pillows usually have more dust mites and fungi than feather pillows (there's a "miniature ecosystem" in all of them, he said). It could be that more allergens accumulate in synthetic pillows because their covers are usually more porous. More tightly woven covers may be protective, he suggested, though that remains to be investigated. Other recent studies have had similar findings.

What may help, though, is the use of impermeable pillow casings to help reduce dust mite exposure. And, of course, changing pillows frequently.

The article didn't say how frequent is frequent, but I dare say it must be more often than once every half a dozen years. Well, I don't have dust mite allergies, but I need a change, nevertheless, if only to feel and sleep better. I was originally thinking of just getting those ergonomic contoured types, but boy, are some models expensive!