One of my pillows was a shade of YELLOW and it occurred to me that this particular pillow has made it through almost 8 years of my life. Sadly, it looks dingy and old. However, it doesn't smell and it's one of my favorite pillows to sleep on but it got me wondering: how long is too long to lay your head on the same pillow? Do they have a shelf life?
There is a rule of thumb for replacing mattresses but there isn't a standard for pillows. Re-Nest suggests washing your pillows at least once a year, keeping in mind that this will strip the filling of some of it's original makeup. This would suggest that it's not that uncommon to have a few good pillows for several years.
In the end, I've decided that it's up to the look and feel of the individual pillows. While mine doesn't smell, it is yellow, which signifies dinginess in my brain, so I'm going to go ahead and replace it.