We recommend usage of twice per week for the two months for up to 30 minute sessions at a time. After the first two months, it is okay to dial down the sessions to once per week thereafter for the next 6 months. You'll notice that the colors of the foot bath aren't as pronounced over time, which is an indication that the detoxification is running it's course. We also recommend replacing the array once per month if usage is at least 2 times per week. If using 1 time per week, once every two months is sufficient.