Can you give an example? I can't think of any everyday situation that most people would run into where calculus comes in handy. It's definitely necessary for certain specific applications, but not ones I'd call everyday situations.
A lot of things are governed by differential equations, so understanding how they behave is helpful. Financial models, physics models, biology models commonly use them.
> Financial models, physics models, biology models commonly use them.
In what specific everyday situations would most people find these useful? It's not like it's common for people run into situations where they say "if only I could calculate the predator prey systems" or "if only I could calculate radioactive decay." I've studied these, and I don't think I've ever run into some everyday situation where I've said "Man, I'm really glad I can apply my differential equations/vector calculus/etc. here." Even in the rare situation where I want to calculate compound interest I opt to just use a interest calculator since it's quicker and less error prone than doing it by hand.
> I don't trust the experts, if only I could build my own disease spread model with partial vaccination - then I could compute the nash equilibrium strategy for the vaccinate-don't vaccinate game.
