muffler and brake shop

The only example(s) I know to point to is the difference between the "box stores" like Midas and others, and a couple of small independents I know, ONE in particular.

He started VERY small, but is a HELL of a welder, and can "scratch build" just about any system, including certified stainless welding and aircraft work.

You need to be ready to work on about anything, and be able to adjust your work to the situation. That means motorhomes, boats, whatever. So this means you need the proper hoist(s) for such work. Not everybody is gonna want a bow -to- stern stainless tuned 4" super duper system. Sometimes, all they want is a simple tailpipe or muffler. SOMETIMES you might be better off just ordering a parts store replacement and slamming it on there.

If you cannot or are not already equipped for oxy/ acet, mig/ tig/ stick welding, and are comfortable with slag in your eyes, you are wasting your time and money.
UNTIL YOU BUILD a reputation for that kind of "detail conscious" work, and can OVERCOME the loss of business to the sheeple who blindly go to Midas and other hi - volume, low service outfits, you are gonna be eating a lot of tuna fish sandwiches.