I guess every time I throw something away. I hope I'm not hurting their recycling program by mixing trash with glass (or vice versa)!
On Post we throw things away American style: eggs oozing between papers, oatmeal sticking on boxes. Behind the scenes Koreans under contract with the Army divide our trash. I always apologize to the faceless contractors when I throw things away. I even try to keep my trash as neat and organized as possible.
Off post everyone must recycle. If not, you can not throw away your trash. People buy different colored bags for each category of recyclables. People keep small "wet trash" bins near their sinks(my friend keeps hers on her counter) to collect the random pieces of food and gunk from plates. One friend of mine has the weekly chore of separating her family's trash.
Trash is collected at a local dumping point on the street. I often see colored trash bags in heaps. High rise apartments have tidier collection points.
Usually people who live off post bring their trash to dumpsters on post. That way they don't have to buy colored bags and separate the trash!
If the military would just teach us how to separate trash, so much money could be saved! I hate the thought of contractors doing our dirty work!