well, with only 300 miles on the odo i am still breaking in. i think that the way you use your brakes is important too. if you can avoid panic stops i think it's better for them.

as for the engine, i plan on mobil 1 at about 1500 miles with the thinking being that my break in period will be pretty much over by then and then again every 3k miles. i have a friend who is a former racecar driver and his position on breaking in an engine was to drive it exactly like you would if it were already broken in, so that it would get used to things that way. i tend to trust the auto mfgs more than his approach, but thought i'd throw out what he used to say about breaking things in.