Sterilight UV water system quartz tube question- Bonus... Now With Answer!

[terracore]

Is there any point in checking the quartz tube?  The manual is kind of vague and removing and replacing the quartz tube is a huge PITA. Because we use rain water I speculated that there wouldn't be any mineral buildup and didn't check the quartz tube at the first annual UV light replacement.  When I did check it on year 2, it looked fine.  So the next time I waited three years before checking it, and it looked the same after three years as it did at 2 years.  At this point I'm ready to wait 5 years before checking it again, or is that a waste of time as well?