system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How much of an effect do daily vitamins have on someone? Is it ever noticeable?

I take one of those daily vitamin/calcium tablets every day cuz I'm sort of a picky eater and I just keep wondering to myself how much they really even do cuz it kinda seems like they don't do anything.
gpt
Assuming you're eating a reasonably decent variety and quantity of food, and have no other outstanding medical issues that would require a supplement, they don't do all that much. If your diet is unusually narrow or light, then they'll smooth things over a bit (i.e. you won't get healthier, but you won't get sick either). It's mostly a form of preventative medicine that covers gaps left by a bad diet to stop you from developing issues in the first place.