You'll hear different schools of thought on "break in."
Some will say you have to smoke through different portions of the bowl (full bowl, 3/4, 1/2 bowl, 1/4) to develop a good cake. "Breaking in" is essentially building a protective cake on the bowl, keeping the briar cooler and drier.
It seems many will gravitate to a good Burley blend for this as it develops a nice cake.
Others will say quit worrying so much about it, just pack it and light it. I'm of that camp.
As long as you clean it well and give it proper down time between smokes, you'll be fine. Look at it like this; our grandfathers didn't pour over their pipe smoking on internet forums. We tend to over-think things at times. They smoked their pipes to the point of having so much cake that the bowl was closing up, then they got rid of it and bought a new one at the local drug store. And you can still find and buy those estates, clean 'em up, and smoke em good as new. I think you'll be hard pressed to find any "new age" pipe smoker ever letting his pipes get to that point. Personally, I run pipe cleaners through the airway and around the inside of the bowl after every smoke, basically preventing any true cake formation. I guess I just like my belongings to stay "new" as long as possible. But I'm now working with enough of a rotation that they get plenty of rest between smokes so I really don't worry about stressing the briar.
The take away from all this?
Just smoke your pipe, enjoy it, don't let it get all nasty.
Everything else is just what you make of it. Part of your routine if you enjoy it, a headache you can leave aside if you don't.
Bottom line really is the enjoyment. No stress. You can't really screw it up too bad, and anything you think you do screw up, someone here can help you remedy!