Have you ever forfeited your points?

[MisterDisney]

Wondering if any of you have ever outright forfeited your points on any given year/years (because of either inability to rent for any reason or cancelled vacations, etc). It seems as though DVC contracts could pay for itself rather easily if during any years you werent able to make it to Disney by renting out your points. It seems as though there are times where maybe there are a "glut" of points to rent out there during certain times of the year, but I dont know this to be the case.