The Virtual Art Academy is designed to cater to everyone from those who are more casual about their art, to highly motivated painters who want to take their skills to a very high professional level.
If you are a serious painter, to build up your foundation skills from the ground up over four years, it would take about 8-16 hours per week. However you can spend more or less time depending on your needs and time limitations. And of course to what degree you want to build up your skills.
How the time is calculated
Basically the four year program is 192 lessons, or 48 per year. That works out to about one lesson per week. Each lesson has from one to sometimes four assignments, about two on average. So thats about two assignments per week. Each assignment takes between 4 hours if you do the minimum, and 8 hours if you do more repetitions. So that works out to 8-16 hours per week. Then add in your free painting time.
It is a good idea to do some regular work on the assignments in the program. If you have the time you could also set a few hours a day, but if you don't have the time, set aside one or two periods a week when you work on the assignments for say two hours. As long as you are working on the assignments you will see steady progress. It is better if you share them to the online campus so you can get interaction and feedback from other students.