I have not gotten fitted for two reasons. 1) I am a broke college student and this whole new irons thing is probably just dreaming. At least until next year when maybe I can gather some gift cards. So I am basically just looking for suggestions of clubs to watch out for. 2) Since I obviously hit better or worse on different days with different clubs I don't want to get fit for the "right club of the day" if you know what I mean.
Good thing is, if you were to go to a good fitter, they will work with your swing. Your swing path may change a little etc, but your swing speed will be fairly consistent. A good fitter will be able to pull a great idea of your true swing on any day. As long as your not crazy inconsistent with your swing, you will be fine. You don't have to go in hitting the ball perfect... in fact, you may want some of your regular misses in there. Thing is, you have to know what your doing with the ball on average... How high do you hit the ball with current clubs? Do you miss left or right? Draw or Fade? Fat or Thin? Toe or Heel? etc?
Always watch for deals on fittings! They practically give them away in hopes of you buying clubs. Many shops will include the price of your fitting towards the clubs also. If you know your swing speed, spin rates etc. you can give a good fitter an idea of what you would need.