2 per bedroom + 1 is the law here. So if you were here you cannot deny a tenant that has 7 or less people.
Like most landlords I require all adults to apply and pay application fee. Lease is written so that each has full financial responsibility.
I have had a 3 BR with 7 (5 kids) and they thrashed the place in a short time span. I kept their entire deposit but their damage exceeded the deposit but not by that much. I did not try to collect for the additional damages but would have if they had significantly exceeded their deposit.
It was amazing the damage they did to the carpet. They also had ringed a beautiful tree that I brought in an arborist to save (fee taken from the deposit). They had also knocked down a fence but blamed the utilities reader but neighbor states they used the gate like a carnival ride and the kids broke fence (I suspect kids broke fence, set it back upright, did not tell parents, utility reader knocks over broken fence, parents believe utility reader broke fence). I did not collect for broken fence (too hard to prove even with neighbor's statement).
So tenant basically covered all damages but my turn around on the unit was almost 2x normal (I typically takes me less than 2 weeks to be able to show a property). Much of this was arborist time to save 2 trees with heavy trunk damage.