Results will vary depending on your commitment to Pilates. Generally, clients begin to feel these benefits within one session and start to see them in ten to fifteen sessions.
That really depends on what your goals are and what else you are doing. If you are only doing Pilates as your workout and your goals are to get in shape, maintain shape or build strength/tone – you could do 4 or 5 classes a week and see great results. With any exercise – it’s important to take a day off and rest from time to time.
Pilates himself said, in reference to practicing Pilates, "you'll feel better in 10 sessions, look better in 20 sessions, and have a completely new body in 30 sessions". To put this statement into perspective, any movement program that is practiced regularly (at least 2 times per week) will offer benefits after 30 sessions.