I have been vegan for 4 years, but I have never taken supplement pills. It has crossed my mind a few times, but I never seem to be able to convince myself that there would be any real need for me to, especially after checking occasionally with chronometer. Before I hear the obvious: I get more than 100% of the RDA/RDI of my B12 from fortified foods, such as soy milk and the metric ton* of fortified nutritional yeast I eat every week. As per calcium and D, I am over 100% on those as well in my daily intake. As far as I can tell, I am not significantly below 100% on any of the vitamins and minerals that I am aware of.
So, to take a supplement pill or not to? I've heard many opinions on either side of it. Ranging from absolutely needed to "well, it helps cover the bases" to claims that supplements are harmful or even just pointless. The later often revolving around the body's lack of ability in absorbing and/or utilizing the nutrients in the pills, or even that high levels of certain nutrients can interfere with the absorption and bio-availability of other nutrients.