I still think this must be "area of the country" specific. I don't know of ANYONE in this area, the Piedmont of NC, that pumps their septic systems unless there is a problem. Only one household of my family or neighbors or anyone that I am aware of has ever had problems. The one that did have problems had standing water due to a faulty install for a mobile home. It failed just about from the very beginning.
TBN is a pretty big base of users. I'm curious if any other NC TBN'ers pump as preventative medicine. As I said, I know my parents place was built in 1971 and has never once had a septic system problem and has never been pumped. My grandfathers place was built in 1957 and has never been pumped or had a problem. We just sold it last year. We also take NO special precautions around here. We don't particularly pay attention to chemicals that go down the drain. All toilets and washing machines and dish washers go to the septic system, so they are thoroughly worked. It must just be down to soil differences in different parts of the country. In NC all grey water, by law, must be handled just like black water.
As a side note, I saw in other threads here a while back of something called a shallow well. TBN is the first I had ever heard of such a thing. I had always thought that wells must be hundreds of feet deep to give good filtration and clean water.