A simple self-examination standard for deciding whether to change the pillow:
1, in the absence of other physical diseases, after morning, often feel the neck numbness acid rise.
2, the pillow has lost its elasticity, need to be slapped for a good while to restore some flexibility.
3, after finally adjusting the pillow, it quickly returned to flat.
4, Pillow has caking, uneven phenomenon, and filled with damp odor.
How long the pillow is suitable for replacement: There are many people change the pillow every four years, in fact, the pillow should be replaced every 1-3 years.