Our bylaws indicate that elections for all positions are held annually. There is no limit on consecutive terms, which I feel is a good thing. Too often you just can't find someone willing to step up, so preventing someone willing would not be in the best interest of the group.
At elementary we did the same as Critter's group. At middle school it is yearly with no term limits. I think that is mostly because it is just incredible difficult to find anyone to take a position, so if someone wants to stay in it for the whole 3 years their child is there, then they are welcome to it. This is a very small group and we just all do everything.
We have one year terms, with a 2 consecutive term limit. I'm not a fan of term limits in public office, but for the PTO, it encourages new leaders to emerge.
Most positions: 2 years. Some positions: 1 year. Although a person may not hold the same position past the term limit, there is no limit to the number of times a person can run for/hold other positions on the board.
