I picked up a smart phone a few years ago (late adopter here), and I sometimes use it to help me sleep. Listening to an audiobook with earphones puts me right to sleep. I set a 15 minute sleep timer and seldom need to reset it. Reading a novel does that too, but the phone is lighter and water-resistant, and has other uses.

I also use bike touring as a detox trip away from caffeine and alcohol, both of which disrupt sleep.