When do you not need a personal trainer? You do not need a personal trainer if you are the kind of person that is motivated and conscious about your physical health and your body’s appearance. If you are a person that gets up in the morning, run 3 miles, and eats a sensible breakfast, there is no need to have a personal trainer in your routine. You do not need a personal trainer; if you’re confident that what you are doing physically is keeping you healthy and keeping you looking the way you wish to look.