Thankfully, my old Honda runs well on regular. I had a Toyota Sienna once that "recommended" premium, so I'd run one tank of regular and the next tank, premium. Of course, this was when gas was much cheaper.
Fanbelt, it's an old wives tale that premium makes a car run better. It's just that premium, on some cars, prevents "dieseling," a condition marked by stutter and shake upon shutoff. If you're car isn't dieseling, and the manufacturer doesn't suggest or require premium, regular is what you should be running.
If you're having irregular idle problems, I suggest a cupful of rubbing alcohol just after a fillup. Or, you can try some fuel treatment.