For many children, piano lessons can be done one time or two times per week to be successful. For those that want to learn at a faster rate, work with the instructor to develop a program that works better for your individual needs. This means using piano lessons that fit your schedule too.
The great thing about many different types of piano schools is that scheduling a practice or lesson doesn't have to be difficult. You can actually do so through a variety of flexible training that is available. You can pick a schedule that works for your specific needs.