A number of times I have seen too many firefighters on porch roofs. Years ago, a great entertainer, Jimmy Durante, (ask your grandpa) had a signature expression. "Everybody wants to get into the act," he would say. The minimum number of people should be used for any operation.
If you look at pictures of Navy fire fighting you might sometimes think that it was most important to keep the hose up off the deck. Even in fire fighting school where we tried to show how three men could do the job, their own petty officers, imbued with a Navy motto, "the devil finds work for idle hands", would put additional men on the line.
The building is your enemy. Know your enemy and know the rules the enemy plays by.