I always thought I could handle caffeine, as I can drink loads of tea/coffee and have no problems dropping off.
I listened to a podcast on caffeine, and they said that caffeine affects the depth of sleep, you sleep lighter, and have less deep sleep, so back in the middle of Jan, I decided to give/drastically reduce caffeine.
It's worked very well, I wake up more refreshed, and having given up caffeine, I don't need caffeine to get me up and running in the morning. I also wear a fitbit, and the stats from that confirm that my number of restless spells in the night has more than halved.