The simple self-examination standard for judging whether to change the pillow:
1. In the absence of other physical diseases, the neck numbness often rises after morning rise.
2. The pillow has lost its elasticity and needs to be patted for a while before it can recover some elasticity.
3. After finally adjusting the pillow, it quickly returned to flat.
4. Pillows have agglomeration and unevenness, and the filling has a smell of moisture.
How long to use the pillow is suitable for replacement: There are many people who change the pillow only every four years.