Start at the Sanctus...

Today I sat in a coffee shop for two hours and rehearsed fifteen minutes of music in my head.

2 hours.  15 minutes.

Sometimes I gestured.  Sometimes I made notes in my score.  Sometimes I sang a line (quietly).  Sometimes I did nothing outwardly but was listening to the different lines in my head, hearing the music, shaping how I wanted it to sound.

And I barely got through the 15 minutes of music in those 2 hours.  I may have rushed the "Agnus Dei" of Haydn's Little Organ Mass so I could hear the entire piece in my head.  I'll start at the "Sanctus" next time.