Until I developed peripheral neuropathy and had fasciculations myself, I never knew anyone else who had them or who talked about it. Fasciculations talked about here involve a duration over a period of time with relative frequency, with no other cause such as over exertion. It doesnt refer to a twitch here or there.
For people with peripheral neuropathy it signals that there is involvement of the motor nerves which are affecting the muscles.

I did work where there were periods of time of extreme strenuous exertion and high stress and never had them before my feet started going numb. I never heard of anyone at work having them either. I dont think they are all that common.

I do know people that have twitching that lasts but eventually goes away. Again I think its more common but some people simply don't talk about it. When someone asks me in the store or at work "how are you doing" I don't reply "well I'm having some persistent fasciculations, how are you doing?" lol

My sisters, wife and mom have had fasciculations that simply go away with time.

Before i had normal twitching, but after my unndiagnosed neuropathy, began, my twitching went hay wire, i get twitching in unusual places, but its more random than pins and needles feeling, or loss of feeling, but im pretty sure its related.

if your sisters plural and your mother have periods of fasciculations maybe you should be exploring a genetic cause for your symptoms or maybe they are all under stress.

Besides low magnesium, low blood sugar spells is a common cause of twitching muscles:

http://symptomchecker.webmd.com/mult...ns=49|50|49|50

I read a book on hypoglycemia once that claimed up to 70% of people having a low sugar attack will have muscle twitching.
Low blood sugar also causes feelings of anxiety, and since that topic comes up here often, it needs to be addressed again.

The best way to deal with low sugar attacks is to clean up your diet, avoid white carbs and sugar and eat balanced meals with some protein in each one, and lower glycemic vegetable or fruit carbs. Some fruits are lower than others. Bananas are high and peaches much lower, for example. Investigate the Book or online by Dr. Barry Sears who developed The Zone diet. Eating this way is rather easy, and controls blood sugar as well. The Zone encourages the consumption of Omega-3's also, and limiting inflammatory high amounts of Omega-6's. A high inflammatory diet is going to release cytokines from the Cox-2 enzyme and those may trigger the twitching.