In Pilates, as with many other fitness systems, performing workouts a minimum of three times per week is a good rule of thumb. This is a schedule that will increase strength, flexibility, and endurance. However, it should be thought of as the minimum, not the ideal. The Pilates founder and other experts suggest increasing that to four per week to get the maximum benefits of Pilates.

Benefits of pilates :

• improved flexibility

  increased muscle strength and tone, particularly of your abdominal muscles, lower back, hips and buttocks (the ‘core muscles’ of your body)

  balanced muscular strength on both sides of your body

  enhanced muscular control of your back and limbs.

  improved stabilisation of your spine

  improved posture

  rehabilitation or prevention of injuries related to muscle imbalances

  improved physical coordination and balance

  relaxation of your shoulders, neck and upper back

  safe rehabilitation of joint and spinal injuries

  prevention of musculoskeletal injuries

  increased lung capacity and circulation through deep breathing

  improved concentration

  increased body awareness

  stress management and relaxation.

A Pilates Workout Schedule That Works for You
The bottom line is that you have to create a workout schedule that works with your lifestyle. Three or four workouts per week are ideal, but anything is better than nothing. Do keep in mind that twice a week is probably the least you can do in order to maintain your level.
 
Can you do too much? If you can do some Pilates every day, great. Just be sure to keep your workouts balanced and varied enough to keep you motivated. It is important to vary the intensity and focus of your workouts. Not just because your body needs rest time to recuperate and build stronger muscles, but because Pilates is about keeping the mind engaged with the body.
 
As Joseph Pilates says, Contrology [Pilates] is not a fatiguing system of dull, boring, abhorred exercises repeated daily "ad-nauseam".