My tank has been up for over 15 years. I have never broken it down. I have changed from a canaster, to a wet/dry to a LR to a SSB and LR. My sand bed is shallow, as it was added 2 years ago with the rock in place. there was a fair amount of "grunge" on the bottom when I added the sand.
Anyway, I have had "crashes" when I did not pay enough attention and ph and other criteria got out of control. These were cured with major water changes and paying more attention. I do not change water as a rule.
I do use polyfilters, which remove heavy metals. I run it for a couple of days a month.
The biggest improvement is my tank has been the shallow sand bed and kalkwasser. These two items have made my tank better and even less work (even though I do have to make up kalkwasser ;-)
So, maybe OTS is just not taking care of your tank properly. Breaking down a smoothly running system makes no sense, at all. Water changes (as if I do them

), polyfilters, sound bio-filtering, and proper addition of chemicals is all that is needed to keep a tank running idefinately (at least for 15 years!)