And when you say "dig the trench yourself," you mean rent a piece of
machinery and actually dig the trench oneself? How do you know exactly
where to dig, and where not to dig? How likely is one to kill, maim, or
injure oneself or others while doing this? It seems like the kind of thing
the average person should not be allowed to do...

Karen

I dug and installed my own sewer main when we built our new house last year.
Despite the fact that I had no previous plumbing experience, there was no
way I was going to pay some plumber 5-7000 dollars to do it. I guess it all
comes down to your abilities and what you're comfortable doing, and what
you'd rather hire out.

It's been well over a year since the line went in to service, no problems
with it at all.