The same applies to toothbrushes. The doctors of the American Dental Association recommend to change the brush every two months — otherwise, you will repeatedly damaging the gums and spoil the enamel worn bristles.
Do not think that the spice has no expiration date. The rest is still on your grandmother dried herbs, may not kill you — but serious damage to the esophagus can cause. Also, instead of the additional flavor, you get a dish overflowing with unnecessary calories.