In extension to the post on Cordero and Dempster, let's celebrate the career of Joe Borowski for a moment:
Career (1995-present): 405 G, 1 GS, 437.7 IP, 363 K/169 BB, 161/190 leads converted, 128/37 IR/IS
85% leads converted
29% IR/IS
7.46 K/9 IP
3.47 BB/9 IP
What can a manageable workload do for a closer? Well, Borowski made it through his career all the way to 2007 before he saw more than 50 leads to convert in an entire season. His previous high was in 2006 in Florida, at 43 leads opportunities.