Vests were tested against .22- and .38-caliber ammunition under wet and dry conditions. Blunt trauma protection (deformation) was measured according to NIJ standard 0101.01. V-50 testing (the median velocity of five shots that penetrate and five that do not penetrate the armor) was conducted under MIL-STD-662D. With .38-caliber ammunition, light, moderate, and heavily worn vests tested better than the average of unused vests. With .22-caliber ammunition, light and moderate wear armor also tested better than unused armor; and the average V-50 of the heavily worn vests was only 2.2 percent less than the average for unused vests. Results show that even 10-year-old vests do not show significant deterioration, and their ballistic resistance remains high over time. To ensure safe armor, police departments should assess the expected threat level, conduct visual inspections of the armor, and educate officers about proper cleaning methods. 2 tables.