New bags every trip (if I stay multi-days in the same hotel room then same trash bag -- I open it, get out what I want, and then close it again, if I switch to a different hotel, then a new trash bag) and yes, I throw out the trash bags when i leave the hotel room. I sometimes wonder what housekeeping thinks when seeing my trash bagged luggage and the trash bags in the trash when I leave, but I'd rather a few housekeepers than bring bugs home with me. I also don't believe that I'm the only person who travels with trash bags so they've probably seen it all before. There was an infestation at a FOX studio last year(?) that got some press -- I remember that one of the employees would change her clothes before getting home....I would too!