You should replace your pillow once every two years, even with regular washing and fluffing. However, you may want to replace your pillow immediately if: Your pillow no longer holds its shape well
You’re developing constant allergies
You notice a strange or foul odor
Your pillow has mold or mildew
Your pillow has too many stains or discoloration
Keeping your pillows for too long can cause discomfort and exacerbate health problems. Watch out for dirty sheets or mattress protectors that are staining your pillows.