This is a very interesting video I found on Youtube. It is one of the videos I used to come up with my own rules for collecting art. Some are even the same, or based on the same premise.
Another movie that I have recommended to others is Herb and Dorothy. It is a documentary about the Vogels, who somehow amassed a collection of contemporary art worth many millions on the salaries of a postal worker and a librarian. It is a great movie for anyone interested in art or collecting art.