original guvnor said:You're not the only one that is confused Ruby.
I used to think I should just have an oil service and brake fluid change every two years if I didn't do enough miles to warrant an Inspection 1 or 2.
However I now think that you shouldn't do that and so next October I will probably give my car an Inspection 2, even though it will be about 7k miles away according to the OBC.
I've been told that not doing this results in an incomplete service history by the BMW Warranty people, although I know many people on here disagree with that point of view, as I did previously. I might email BMW to see if they can answer unequivocally one way or another.
Yes gearbox and diff oils changed on inspec2. I'm sure if they were that critical BMW would specify every 4 years. These are sealed units and I guess not likely to get contaminated from other sources unlike the engine oil.