I have been playing the AP1 712 irons for almost a year. They are the best irons I have ever owned . I have steel shaft's  S300. I have slowed down my swing and also dealing with some lower back issues . I want to switch to a regular flex shaft. Is it better to switch shafts or trade in my clubs for a new set. I will still play the AP1 712. These clubs were a big investment for me and I want to make the right choice.