It seems like they start encouraging people to give back headsets (and making a lot of annoying announcements that create pauses in videos) around 40 minutes prior to landing. If you push it, they will usually let you keep the headsets and keep watching your video until about 10-15 minutes before landing. So why do they try to rush you into giving up your headset? Do they really need that much time to prep the plane for landing?

Any ideas?