This is one of those bits of pipe smoking minutiae that draws heated debate.I searched on site could not find info on new pipes and how long to break in or is that even real?
There are many who not only state that breaking in a pipe is real, but vitally important to the long term maintenance of the pipe and to producing a cool smoke. They argue that certain thickness of cake is desirable, and that a new pipe has to be smoked so many times before it performs to its best. Some even go so far as to have specific blends they devote to breaking in a pipe, similar to how one may season an cast-iron skillet.
There are also many who believe that breaking in a pipe, though not entirely made up, is grossly exaggerated or even unnecessary. Such people state that a thin layer of carbon at best is what is necessary to insulate a pipe, and that a well-made pipe properly smoked and cared for will not need a thick layer of cake. It's easy to ream a pipe incorrectly and damage the pipe, which is viewed as an argument against building a cake and being overly aggressive in breaking in a new pipe.
If you are curious, I mostly fall into the latter camp, though I do acknowledge building a cake as a means to season a pipe for a specific blend or genre could potentially be beneficial. To me, however, that is a lot of work for very little reward.
But this is something people tend to, for whatever reason, feel strongly about. It's something you will have to find out for yourself.