Always have a multivit and a vit D tablet with breakfast. Been doing that for years, I just order them on line, none of this pissing about with going to the shops.
Don't know if it does any good but the way I see it, it can't do any harm. And the vets reckon most people in Northern Europe are vit D deficient as there's just not enough sunshine and even when there is we're often indoors working.