Former NB Premier Frank McKenna promised to only stay in power for only 10 years and kept his promise.
If someone has been in a position for an extended period of time, they bring institutional history with them to the table. Someone who isn't a rookie and has been around long enough to feel comfortably well versed in the inner workings of a school board could provide energy with a mix of knowledge. Someone who is new to the job can bring a new perspective and a different vision to an organization. This vital mix of experiences benefits an organization when new ideas can be infused with current ones.
How does anyone know when experience becomes stagnation and a lack of new ideas? Since the terms of school trustees have been lengthened to four years, I think it is good for there to be a limit of four terms. 16 years as a trustee allows for experience to be handed down to new people coming on board. There is no legislative requirement. I don't think there necessarily needs to be. However, I personally pledge to remain only for a maximum of 4 terms (16 years) if I am granted the opportunity and earn a seat at the trustee table.
Change does not work and cannot survive if it comes about as a result of a cult of personality. Change has to be embedded into an institution's culture.