Excellent question!
Patrol time was traditionally utilized in two ways: planning for the troop or patrol outdoor activity that month, or sharpening scout skills that were based on the theme of the month, and the competitive game that followed patrol time.
Outdoor activity planning: menu, food list, duty roster, looking over patrol gear for cleanliness/accountability/good repair, arranging transportation, and such. If the event was a camporee, the patrol leader reviewed the camporee package, discussing special requirements, competition, expectations, etc. Patrol leaders were expec