We know what the manual says about the "break in periods". Every vehicle I've had seems to have different break-in periods for different aspects. The clutch on my last Infiniti G35S took over 5,000 miles to break in and settled in around 10,000 miles. Thought it might be interesting to see what people are experiencing with their X5s in any aspect of the vehicle over time/miles.
I've only had mine (30i) a week and it has only about 225 miles; I've got nothing valuable to contribute yet. Noticed a few things but it's way too early to glean anything from them. If I have to brake while turning in an intersection, I feel a bit of hesitation when I hit the gas which can be followed by rev higher than I'd expect. I live in a smaller town with few traffic lights and major roads are state roads with 2 lanes each direction (with suicide/turning lane between); this allows longer runs at steady speeds and it seems I can keep the MPG needle higher using the manual shifting mode. Of course, I am still on my first tank so no basis for real comparison! Lastly, the seat (Nevada Leather) feels quite stiff/hard, stiffer than I remember from test drive. I'll likely be putting another 500 miles on her this week.
So, what changes are you seeing at various mileage and/or time frames for the ways your vehicle behaves? MPG, acceleration, braking, handling, suspension, etc.?