Yoga is not a physical practice nor a sport
It is possible that at the beginning you practice only two or three days a week but Ashtanga Yoga is a method designed to be practiced 6 days per week. We must also rest on full and new moon days. This is the only way of practicing Ashtanga correctly. If you practice just two or three days a week, it will be a superficial practice and you will never understand or reach the physical, mental, emotional and spiritual benefits that this practice provides us.
The Krishna Pattabhi Jois Ashtanga Yoga Institute (Mysore, India), founded by S. K. Pattabhi Jois in 1948, is the site of reference for any practitioner of Ashtanga who wants to learn from the source. His grandson, R. Sharath Jois, is currently the director of the Institute and is responsible for transmitting this method of yoga as learned from his grandfather for over 25 years.