Rate-Improvement Mortgage

You had an adjustable mortgage. It was locked for your first two years, and then it floated as LIBOR plus 200 basis points. And in these last two years, LIBOR went from 3.5% down to 2%, so your 5.5% old 2-year locked mortgage (on its two-year anniversary, if you refinance it so that your rate improves) is now 4%, saving you 1.5% a year on the $300,000 you'd borrowed for the white-picket-fence-lined haunted house with the BDSM room downstairs.

That's a savings of 4,500 a year, every year, at least until you pay down the dough.