At some point in the past (I don’t remember exactly when) the substitution rules for Australian junior tournaments was changed to allow more substitutions. One of the reasons put forward for this change was to provide greater opportunity for players to play by giving coaches more possibilities to redistribute playing time. I disagree with this reasoning at two levels.
Firstly, I philosophically disagree with the implication that a player’s experience in a team is a direct function of the amount of playing time that player has. When I was fifteen my first main coach taught us what it meant to be in a team. He taught us about roles. He taught us that by working at our maximum in practice we made other players better not just ourselves (co-opetition, but 20 odd years before someone put a name to it). He taught us how to play the right way. He taught us that not every player gets to play the same amount, and that amount depended on the work you put in. And he taught us that when we won a medal, which we inevitably did, every player had contributed to it and every player deserved it. If you don’t learn these things, you miss out on so many shared, wonderful experiences. Measuring the value of an experience using playing time is shortsighted and superficial.
Secondly, by adding substitutions to redistribute playing time, fewer and fewer people actually get a chance to play volleyball. Volleyball is unique precisely because its rotation rules demand that every player has to play every position and therefore must learn every skill. Over time coaches have invented systems to get around this and the libero has obviously had an effect but it essentially holds true to this day. That everybody has a chance to do everything is not only unique, it should be an attraction. Allowing extra substitutions might redistribute playing time but that playing time isn’t playing volleyball. It is playing ‘defence’ or playing ‘blocking’. And of course one of the attractions of specialisation for coaches is that they don’t have to spend time practicing ‘unnecessary’ skills.
The final consequence is that players don’t learn how to play volleyball. They don’t learn about teams, or about roles. And dare I say they never have a chance to develop a love for the sport and therefore drop out the first chance they get.
Women’s volleyball in the USA has similar issues. They recently increased the number of substitutions allowed to 15. In response Terry Pettit wrote, far more eloquently than me, in the most recent edition ‘Coaching Volleyball’.
 That coach was John Dunstan. The lessons I learnt from him I still use every day.
 If you couple this with the movement to restrict numbers in a team to 10, then you have players who never even get a chance to practice playing volleyball.