plwk wrote:So, if the Vinaya is silent on the age limit, why do individual monasteries create and impose such?
The monk I interviewed cited several reasons for the rule at Abhiyagiri.
First of all, the monastery is built on a big hill. Every day the monks walk up and down that hill, with a steep grade, several times. Any monk there would need to be excellent health, and hopefully still be in excellent health 10 years from now.
The training for a beginning monastic is roughly a 5 year program. A monk is considered a leader in that community after about 15 years. The hope of the monastery is that junior monks will travel and stay at other monasteries worldwide as part of their training. It is also hoped that 15 year monks will move on, either to start new branch monasteries or function in leadership roles in monasteries world-wide. Consider a monk who ordains at age 30 versus a monk who ordains at age 60, regarding a 5-15 year program.
The monks care for eachother in times of illness, this is their social contract. But the monastery is not set up for long-term convolescence care, this would put a lot of burden on the other monks. So they try to have a mix of monks who are younger and older, so that they don't have too many monks reaching elderly ages at the same time.