You should wash your pillows at least twice a year to keep them fresh and clean. If you eat in bed, have pets, or sweat a lot, washing pillows quarterly (every three months) is recommended. Special pillows like body pillows or throw pillows should be cleaned every 3 to 6 months depending on usage

. Key points on pillow washing frequency:

• Standard pillows: wash every 4 to 6 months.
• More frequent washing (every 3 months) if exposed to more dirt, sweat, or pets.
• Pillowcases should be washed weekly to protect the pillow.
• Memory foam pillows usually cannot be machine washed; clean covers and spot-clean the foam as per manufacturer instructions

Replacing pillows every 18 months to 2 years is advised, especially if they become lumpy, lose springiness, or accumulate allergens

. In summary, washing pillows twice a year is a good baseline, increasing to quarterly if conditions warrant, while pillowcases should be washed weekly for hygiene