Not a legal opinion and not all inclusive, but I'll add my penny's notes from a recent teleconference sponsored by the New England Land Title Assoc. given by an IRS agent:

Notice of Federal Tax Liens.  "A lien usually releases automatically 10 years after a tax is assessed unless the statutory period for collection has been extended and the effect of the lien has been extended by re-filing." Liens issued after 12/31/1982 are self-releasing.  The newer liens only include the last 4 digits of an individual's SSN or the full EIN for a business. The IRS can continue the lien within Ten (10) years plus 30 days from the "Date of Assessment" if it re-files.  Example given: "Assessment Date" on Lien 06/30/2004; "Last Day for Refiling" on lien 07/29/2014.  The agent mentioned it is possible the IRS could re-file the lien anytime after 07/29/2013.

I'm old school.  I always make a copy of the IRS liens and add my personal notes to it.  Leave it up to attorney or title company to make decision.  Bankruptcy, offers in compromise, miltary active duty and other "stuff" can mess this black-and-white issue up.