it’s not number of appearances. It’s rate. Appearances or pitches over time. Time is the constant and as RB pointed out, the key to maximizing quality is finding the sweet spot for individual pitchers of rate of pitches over time that they can throw the most highest quality pitches over the constant. No two people are the same. Some throw 100 every 5 days, some throw 60 every 3 days. Some throw 30 every other day, some throw 45 two out of 5 days, etc. That’s where your analysis comes in. Chart the metrics on where your leading indicators (velocity, spin rate, swinging strike rate, et al) drop off. Rather than defing your pitching capacity based on something arbitrary like “role” or not defining your capacity and rely on pitchers based on necessity, define your pitching capacity based on the pitchers performance.