I followed this approach last year.  During each session the teen was required to volunteer every weekday during the session and attendance was mandatory.  I had to relieve 3 teens from service for not following the attendance requirement.

Most of my returning teens did not return because of the new format.  And some potential new teens said they simply could not get a ride everyday.  However, the ones that did participate seemed to really like it and the staff was very happy.  This format gave the staff a chance to really get to know the teen assigned to their areas. 

I also found this format to be much easier on my staff.  The first day of each session was a little hectic as we started the new teens but then we had 3 weeks of "down" time, as the teens were pretty self sufficient once they got started.

I will be sticking with this format :)

We had 61 teens this last summer.  This is about 40 shy of what we normally have.  We have about 30 departments to chose from for placement.

A teen volunteer can choose to do one shift or more than one shift...our shifts are 3 hours long.