Hi James,
In House can be good because you don't have to give up a portion of the money, but using an outside vendor can be useful because they have the power to garnish paychecks or seriously affect a former residents credit score.
Personally, I've had a fair amount of success with in-house collections.
12 years of Catechism School = one dozen years of guilt trip experience. :ohmy: If the departing resident has (or is able to borrow) the money, they usually write me a check the day they turn in their keys. I prepare them for this by being forthcoming about potential charges before move in, during residency, and right after notice to vacate.