This has all been really interesting to read. I've had my haibike with Bosch motor for 3.5yrs now and use it for commuting 20miles a day in all weather's. I also spend 4miles of that on the seafront which means sand....a bikes worst nightmare. I'm pretty good at keeping it clean / lubed (no pressure hose) but I'm certainly not perfect.
My BB had a bit of play so my local bike shop contacted Bosch who said replace the motor. However, I then contacted e-bike in Farnham where I had bought it and they were happy to replace the bearing. When he had finished, he showed me the remnants of the old bearing...totally shredded. He said it was the worst he'd ever seen!
The replacement has the plastic protector so hopefully this will give it a bit more protection in the future.
However, after seeing these posts, particularly energiserbunny, if I need to replace the bearing again, I might have a go myself.
Overall, I still love the Bosch drive and it makes my commute effortless. However, I have been suprised by the maintenance costs of the bike, chains, sprokets and cassettes that get eaten by the extra torque. I'm still trying to find the prefect option....cheaper parts that I replace more often or expensive parts that last a bit longer. Latest attempt is the connex ebike chain and the 20tooth sproket to hopefully save the 11tooth on the cassette getting trashed after 3months..let's see how that gets on...