yes, there is that. there is also balancing them with other minerals. supplementing one thing can cause a deficiency in another. then there are things like iron and copper where the body wont uptake them due to sensing there is enough bot what is in the body is unusabel due to oxidation(thanks newport).
i just go by intuition. if i think i need it i put it on the shelf. if i feel i need it i take it that morning. if i dont, i leave it be.
without fail i take Iodine and boron and selenium. almost always zinc with copper. the rest are as needed.