Years ago we had a pitcher in Turkey, USAF type, that was good for only 90 pitches. If he went beyond that limit he got beat to death by the hitters. We kept a pitch count to know when to pull him.
I've noticed what I consider to be the same scenario with some of the girls pitching in the games my granddaughter plays. Since I see this one girl pitching quite often I think I'll just keep a pitch count in my head and see if there is anything to this.