There was a time in the minors where Jameson Taillon was challenged to throw three changeups per inning. It's not a productive strategy for results to throw a developing pitch that often. It is productive in terms of developing the pitch.
This is a strategy you see often in the minors. It's not a strategy you see in the majors. Pitchers develop pitches in the majors, but the only focus there is winning. You only throw a pitch often if it gets results.
Last night, Jameson Taillon threw his slider 27 times, which is a little more than three pitches per inning.