Well, the day I have to have my septic pumped is probably the day I will HAVE to hook up to city sewer. But my corner lot is my drain field, and it is almost pure sand on the back half of it, where the field is. Unless we get a foot of rain a couple of times a week, it doesn't even slow down. I dump some yeast / bacteria stuff in the toilet a couple of times a year, use a biodegradeable dish soap, not much bleach, and rarely even use a grease that would harden. I cook with olive oil or rape oil. And I avoid getting the oil in the drain too, but I'm sure some gets there..
When I rented the house to my daughter, SIL, and their child for 8 months, I got to chip grease out of the point where the kitchen drain line drops off to the main line when I moved back in. Got a darn frisbee looking piece the size of the drain and half an inch thick. But knock wood, that's been my only drain plumbing type problem. And I've been here 10 years. I have had 6 people, including 3 or 4 girls and women, living here at some times. Granted the guys went to the fence corner when the sole room was occupied, but the system has done well.
Nowadays to put in septic, you are supposed to have the pumped and anaerobic system which sells for about $6000 - about the same as connecting to the city sewer, and I'm not sure the city even allows new septic. (they annexed us in 1992) Since they ran sewer line through my front yard, when it goes I guess I connect...
Gypsi