One of my clients has been training with me for just over 2 months. Every session lasts 30 mins and on average trains a couple times a week (1hr).
Already people have seen the difference in his shape and he has seen a difference in his strength.
This is a guy that has been a regular gym attender and usually trains for an hour plus
This so proves it's not what you do but how you do it and that's why there are personal trainers in the world cause we know how to tweek things to get the best out of you for you.