BMW replaced mine at 19.1k kms, it was at the 20k service and I'm pretty sure I still had mileage on it. I went for a 6k roadtrip to France so figured better to have it changed. I wasn't a particularly meticulous chain cleaner/luber either and yet it lasted.
Re Scottoiler, personally I don't find de-greasing and lubing the chain that annoying, so happy to live without an accessory (as useful as it may be). One less thing to have issues with. But that's just me obvs.
Congrats on your travels by the way, I have the links on my list to check out. Where will you be going next?