Useless trivia addendum - the fat reclaimed from the roasting pan or from stocks was traditionally used to make roux and pastry. When you add a roux to sauces, gravies, stews, etc the fat in the roux usually rises to the surface and can be used again.

I occasionally make a traditional beef stock that cooks for 48 hours and yields nearly two kg of beef dripping as a by-product - I start with nearly 30kg of bones and other bits and end up with 8-10 liters of beef stock and 2liters of dripping. This is usually the point where the pixie decides that she is over my love of cooking and has a sense of humour failure!