It's not primarily about the reliability. Most of us can make something run.
It's about image. Like it or not, it is an important business issue.
"Don't judge a book by it's cover". Yeah, right. We all do it.
You don't walk in the store that is in the bad section of town, or smells funky, or is run by those (insert ethnic group) people.
Anyone know anything further than the "cover" of those ladies in the GGA thread? Didn't think so.
People will judge your business by the appearance. The problem is that many of those people are pretty important customers.
Your friends will be your customers, regardless of what you drive. The people who love your work, same thing. The people who can not afford your service (who probably won't judge you for the turd you drive) will make lousy customers. The people who may have a little money to spend on the services your business provides are the ones most likely to be judgmental of your appearances, and the ones you need to attract as new customers. Plus, they've got judgmental friends with money who will also make good customers.
If you drive a vehicle that looks cheap, people will expect your services to be cheap, or your quality to be poor, or both.
There is only one legitimate business reason to drive an older vehicle- business branding. So, a VW Splitty Bus for a surf shop, a restored vintage Carryall for a delivery truck for a speed shop, etc. Other than that, you gotta look good, and fairly new.
For a mobile business, the appearance of the vehicle is the curb appeal AND the primary marketing strategy.
My first dedicated work truck was a black Chevy panel van with a fresh paint job and a beautiful graphics job. I frequently met people who would say, "Oh... Fenner Construction. I see your trucks all over town. I hear you're really good". I would smile and thank them. I never told them I only had 1 truck.
I always worked hard to park my box truck where it could be seen. It's a rolling billboard.
I also trained my crews to keep the work trucks clean, and park them visibly everywhere they went.
Over the course of 20+ years, I am absolutely confident that my vehicles have brought me hundreds of thousands of dollars of work. So the question is not how much I would have saved by buying a raggedy truck. The question is how much I would have LOST.