I guess I should clarify the term "regularly scheduled". This means it is not an ignored item. Resin can be "ignored" for many years in non iron, low chlorine installations. Carbon should be scheduled for a regular changeout depending on the installation parameters. In commercial applications monthly to annual changeouts are common, residential applications with chlorine injection, 2-5 years is not unusual. I would not recommend going beyond 5 years. I am trying to figure out how every 5 years is unfair, improper, or in any way contreversial. And in reference to my own equipment, the point was simple, I recommend GAC first, but in my own application, I have it last. The point was to show that an argument either way is going to end up with a 20 page thread... so either way is neither right nor wrong, except in specific applcations and that should be addressed when they occur. How is it that in agreeing with someone, I am wrong? LOL