It's all a bit smug saying look after the bike and you won't get any issues. I ride all year, use ACF50, am a bit of a detailing freak, sluiced the bike down after every ride with cold water in winter, it was garaged, cleaned top to bottom every weekend. Never left wet as I use a bike drier and my RT still disintegrated.
There is a thread in here with pics. It it had;
Engine
Paralever
Final drive
Rear wheel
Centre stand
I could go on and on, it's almost a lottery.
I'm at 7k miles on the K1600 replacement now and it's had a new centre stand on warranty due to corrosion.
I had the backup of the dealer as they told BMW they'd never seen any of my bikes in anything less than sparkling condition.
My R Nine T has had no corrosion issues but it had to have a new motor because the crank case bolts were coming loose. Turned out to be faulty cases so they swapped the engine.
It's not simply a case of "some people don't know how to clean a bike" , there simply have to be issues with manufacturing and the fact that (as has been said before by many) issues with thin, water based paint.
It's not just BMWs, a friends got a 17 year old firestorm, immaculate apart from the starter motor, but they always get hammered, his 10 month old Africa Twin looks like it was pulled from the wreck of the titanic, and he's being faught all the way by Honda at the moment so he's now going through formally rejecting it.
Both my GS LC, and my RT LC had corrosion problems, both had replacement engines, the RT was almost a total rebuild.