I, too, don't take a multivitamin. I'll take a couple individual supplements like magnesium that I know are filling essential needs where I have deficits. I also take vitamin K2 (menaQ7 variety) and vitamin D3 at the times of year when I have little sun exposure. The K2 is specifically to encourage calcium to go where it's needed (bones) and not where it's not wanted (arteries). I keep it simple with these supplements and eat a good variety of healthy proteins and vegetables to get everything else I need.

I'm somewhat skeptical of multi-vitamins as many profess to have everything but the kitchen sink, and I'm never sure how much of this stuff is at the quality where my body can absorb what it lacks or whether it needs any of the other stuff. I know I no longer need iron at my age, and many multi's have this in spades. It's good that you're asking this question, as being thoughtfully discriminating about what you consume will enable you to find the correct combination of supplements. I started magnesium when I experienced muscle cramping during workouts, and it immediately provided relief, so my N=1 lead me to supplement with a good form of magnesium.