In radio especially, it's important to sustain the interest of the listener from day to day so s/he will come back again and again. Radio commercial campaigns have the same function. And a lot of the same challenges.
I wrote a series of radio commercials for Hardware Hank stores a few years back. They were quite popular. Here are two from a series of 10. I hope to have the whole set online in the near future, along with commercials and campaigns.
Hardware Hank Hillbilly