Yup - been there, done that. I now have an ultra-light bag (think very thin, but durable material) in which I have everything I normally use on a flight (noise cancelling headphones, cables, Kindle, Real Lime, etc.). On boarding the smaller bag comes out of my carry on (which goes above), and if I'm not using anything it goes back in my bag in case I forget. I stay away from the seat back because sooner or later I'll leave something there!