In the beginning, you should come as much as possible. Bikram recommends practicing 6 days a week in the beginning! This is not always possible, but at least 3-4 days per week for the first year will promote the most digestive, muscular, nervous, metabolic, lymphatic, skeletal system benefits.  Once you are familiar with the postures, and you become used to the heat, you will enjoy watching experiencing the results of all your hard work. It actually becomes fun!