What are the potential causes of almost daily numbness in the fingers/toes and cold feet?

Autoimmune Diseases. Diabetes is the most common cause of sensory changes in hands/feet. However, more often as not, diabetes starts out with burning pain, leading to numbness . Another possiblity is circulatory disturbances, caused by autoimmune disorders, such as reynauds or buerger's diseases. You may want to visit with you family physician about testing to see if you are haveing vasoconstrictory episodes.
Neuropathy. Some causes of neuropathy are diabetis, chemical exposure, medications, alcohol.
Herniated discs. systemic disease like diabetes, this is something that should be brought to the attention of your doctor as it is possible to get worse if not fixed.