I used to think that personal trainers were for the frou-frou gym rat types -- until I had 6 weeks to get in shape for a bikini contest with my sisters-in-laws in Hawaii (challenged by my older S-I-L who is a very fit and beautiful triathlete.)
I look athletic, but I'm not really. Can swim a mile or so, but not very fast... However, I
am competitive. So I got a personal trainer, and it was amazing how toned I got! He showed me how to work the exercise ball, in ways I never even considered. I was very surprised at how out-of-shape I was, even though I look very fit. He helped me get over being intimidated by weights, and called me out every time I cheated on counting reps...
I would never have been able to get toned so quickly by myself, even if I swam 2 miles a day (because that's pretty much all I know how to do). So I'm a total believer in personal trainers now. Although haven't seen him since the Hawaii trip. Maybe I'll give him a call 6 wks before a school reunion or something