I agree with you in that there is never a dull moment and each job presents a challenge.(the Puzzle ) !
Commercial contracting is a big step up from residential repair & remodel. When you make that leap as a residential contractor it is in most cases because of a lucky break.It's a different game all together.A name in the business helps a lot-that means word about the kind of work you do spreads. When honesty is your policy that goes a long way.
My clients never expected me to front out material monies or the cost of any helpers that were required. I never marked up materials and the client pays the tax on those materials . Keeps the cost of having my tax's done end of the year down. When I go through suppliers I have the supplier add in the tax to the bill.Keeps my book keeping costs down.That in turn saves the client money='s low overhead.
My grand father was a contract electrician and my father was an electrician by trade-I know your method well. Some of my grand fathers ways figured into my business practice.
People like it.
They must because they won't leave me alone and I'm retired- but they keep calling. So I guess it's semi retired from it. The puzzle ,the challenge-it gets you I guess ,perhaps even addictive.
Time and materials it's quite simple.