You never need one. It’s a matter of how early you are willing to arrive at the theater. Arrive early enough, you’ll get in. If you’re going on a weeknight (except for Labor Day), you can most likely go in the theatre 25 minutes early and still get a seat. It may not be as good as some of the FP seats. It may be in the last section, but most likely you’ll get one. If you want to be closer to the center, then you will want a fp and you’ll want to be there at the beginning of the fp window.