> typically without a meal

any reason why? it's fat soluble and absorbs much better if taken with a meal.

Because I always forget lol. My point is that I still had a good effect even though I'm doing an extremely sub-optimal job of taking it/probably getting a dose-equivalence of way less than 2k IU/day.

Unfortunately this is a common error people make, many vitamins and other supplements are absorbed better when taken with food, even if that seems counterintuitive at first.

It really depends. Other things like iron is best taken fasted (and paired with Vitamin C). Coffee also blocks iron absorption, so many people supplement at nighttime. Also things like Zinc and Copper both compete with each other for absorption, so best to avoid taking them at the same time.

If you're optimizing your supplement stack, really gotta research each one individually (and how each impact the absorption of the others)

Another thing I am curious about is time of day too -- I was told vitamin D/Multivitamins were better taken in the morning with food.