"Individual clauses can be reviewed and updated on a schedule that corresponds with normal portfolio monitoring procedures.... [T]he IPS should be reviewed in full on an annual basis to review for any outdated information. Once the IPS is sufficiently old, you and the client (or the courts!) might consider it stale and no longer valid.... [E]very IPS ought to be rewritten every 3-5 years, just to remind the client this is an active and important document and because it needs to accurately reflect the client's current thinking and circumstances[.]"