There are five lifetime Jedi Councillors (Yoda, Mace Windu, Ki-Adi-Mundi, Oppo Rancisis and Plo Koon in Eps. I-III) that served until they either step down or death do them part.
There are four long-term Jedi Councillors, who could step down at any time but their terms of service were time-limited.
And finally, three short-term Jedi Councillors (Anakin was a short-term Jedi Councillor before turning to the dark side) who are usually brought in to deal with a crisis or to bring the voices of otherwise-underrepresented branches of the Order.
So how long are the terms of service of the time-limited Councillors?
Also, which Councillors from the movies were long-term Councillors? Which ones, other than Anakin, were short-term Councillors?