Found it... the actual limit IS ten years, if you serve more than 2 years of a presidency that someone else was elected to (i.e. vice-presidential promotion) you can only run once more......

Like this will affect MY decision to run or not *BG* Frank

The 22nd Amendment

Section 1. No person shall be elected to the office of the President more than twice, and no person who has held the office of President, or acted as President, for more than two years of a term to which some other person was elected President shall be elected to the office of the President more than once. But this Article shall not apply to any person holding the office of President when this Article was proposed by the Congress, and shall not prevent any person who may be holding the office of President, or acting as President, during the term within which this Article becomes operative from holding the office of President or acting as President during the remainder of such term.