I'm Sam Ballard. Vice President of Blankenship's Roofing Service, Inc. Did you know that it is recommended that you replace the pipe collars on your roof every 8 to 10 years. Neglecting to do so can lead to major damage. 85 percent of the leaks that we are called to fix are due to dried out pipe collars. The sun dries them out, they crack up, and it causes them to leak.