"If we over-train via the literature like method and etude books, we're going to know more than we need to know in order to be able to cover the parts that are put in front of us."
The above quote was taken from Sam's fantastic interview in A Band Director's Guide to Everything Tuba: A Collection of Interviews with the Experts. It is a good reminder to us all that we have to encounter everything we'd ever need to do on stage (and then some!) in the practice room in order to be truly prepared.
The best bands perform full run throughs of pieces and entire programs when they are mentally and physically exhausted, yet hold themselves to the same high standards. The people most prepared to win an audition have played the excerpts during their preparations in every possible order including the worst ones for their chops.
Anyone who makes performing look easy has a secret. It is easy compared to what they made themselves do in the practice room.