When I was in college I got myself totally scr*wed up doing the Adelle Davis thing. Two things it did teach me are that (1) everything needs to be in balance, and (2) there's no pill in the world that contains everything we need to be healthy, not least because we don't completely know everything we need to be healthy.
I do take calcium/magnesium because I sweat so much out that I invariably get cramps if I don't. But... these need to be balanced with zinc, and zinc needs to be balanced with copper, and copper needs to be balanced with iron, and on and on and on. So I just take enough Ca/Mg to prevent the cramps, no more, and try to titrate my own dosage through being aware of my sweat rate.
Then there's vitamin C (the only function of which is to build collagen) - so I will take some when inhalant allergens are high (helps keep mast cells from bursting and releasing histamine), and the morning after a very hard workout (you don't want to suppress the inflammatory response during or immediately after the workout, because that's what stimulates tissue rebuilding, but you want to have enough vitamin C around to be able to build the cell walls later).
And I keep some balanced B-complex around. It's amazing how few B-complex and multivitamins are actually balanced. Solaray has two that are mostly balanced - a chewable and a capsule - but even those two are relatively deficient in folate and biotin, because of the limits on how much of those can go into an OTC supplement. I prefer the chewable, because of the lower dosage (both in proportion to the folate/biotin, and in general). Every couple-three months I'll take one, and if I'm not peeing out yellow B2, then I know I was deficient, and I'll take one a day until I start peeing it out. Then I won't take any more for several weeks. When my diet is good and I'm not drinking too much alcohol (which the latter is pretty much all the time, now - a good thing for a bad reason), in cooler weather I pretty much don't even need the first one; when I'm sweating out more, it could be two or three days, is all.
JMO....