We are really blessed to be in a troop with 10 ASMs and a lot of supportive parents. Even when boys turn 18, some of them and their parents choose to remain active. When one ASM was asked why he still did scouting although his boy was over 18, he told the questioner, "People my age don't like to go backpacking and hiking, if I work with the boys, they'll let me go with them on weekends."
Our troop has sign up sheets for every outing. There is a due date on them. They used to be mailed to us monthly but are now sent via email. If you don't receive one, there are copies at the meetings