Wade is absolutely right. Automotive engineers who don't work for any automotive or oil companies will tell you this all of the time. The premium fuel is only a recommendation in modern engines, and modern engine management systems will compensate for all fuel types easily,
100's of times per second.The only time a high octane fuel would be needed is if you have an old high-performance car from the 1970's or earlier which didn't have electronic engine controls.
If you have a high performance car, and you want to go racing with it on a track day or something, then by all means fill up with high-octane that day. If you're driving around town or on public highways with speed limits, you'll never need that level of performance.
Yousuf Khan