How long have you had your pillow? Do you even remember when you bought it? If not, here's a quick tip to find out whether it's time to replace that pillow.
Simply fold your pillow in half, squeezing all the air out of it. If it doesn't spring back into shape after you release, you're due for a new one.
According to Real Simple, pillows should be replaced every three to five years, provided they don't smell mildewy before then. Any longer than that and they'll start to lose support (not to mention accumulating dust mites and other allergens).
In the meantime, make sure you wash your pillows at least once or twice a year to freshen them up.
Read More: Real Simple