There is acceptance that some parts of cars wear out and that other parts need replacing after a crash. Vital safety equipment, such as seat belts, should be no exception to this. This paper reports on recent seat belt studies conducted by New South Wales Road Safety Bureau’s Crashlab, and attempts to summarize the findings. The studies reported on are: 1) An examination of the static strength of individual components of aged used belts systems from a variety of vehicles; 2) An examination of the dynamic strength of a specific series of aged seat belts; 3) A review of aged crash seat belts from a time series of vehicles with matched pairs of crashed worn, crashed not worn and not crashed seat belts.