Depending on your goals, starting point and physical ability, one personal training session may be sufficient, although 1 to 3 personal training sessions per week are recommended. For those just starting to exercise, 2-3 personal training sessions per week are recommended to ensure they develop a proper shape and a sustainable routine. When you have invested in a personal trainer and start exercising, you should try to exercise two to three times a week to build muscle. If you have gym experience, know how to train properly, and are able to stay disciplined, then training once a week can still be beneficial.
Sometimes, people just need a coach to help them stay on track from time to time, which is when you can schedule one session a week. For most people, exercising with a personal trainer twice a week is enough to achieve their fitness goals.