Since I’ve been traveling a lot in the past year, I have frequently instituted the stop and check procedure. Generally, I apply this to anywhere I sit or plop down luggage. When leaving airport seating, turn around and look at your seating area. When leaving your plane seat, inspect the seat, under the seat, and the pocket in front of it if you use that. When leaving a sleeper bus, inspect your seat and any trays or slots. Finally, with hotel rooms always do the room check before leaving. Look in every drawer, shake out the sheets/blankets, and even check the bathroom for forgotten items.
With 9 months of traveling, I only lost 2 things, and my wife lost her glasses in Sapa. I lost a neck pillow that I think I put around my neck and it fell off as I was leaving a sleeper bus. The other possibility is leaving it on the seat I put it on, but I was insistent on not doing that. I also lost an awesome wire that could switch between Apple, type B, and type C. I was using it on a sleeper bus.