I had asked the healthy balance teachers (at the class I was taking) if there is any difference if it's an average of 30 minutes each day for the week or if you need to do it each day. They said that an average is fine, meaning you could do 3 days an hour each, and that would suffice. And I haven't had time to actually do a literature search to see if the difference in negligible or not, but I feel like there might actually be a big difference between averaging it versus hitting the 30 minutes daily.