I started my business in 1999. It took a while to really get off the ground. And even since having some success, there have been a couple of crashes. I even had to file bankruptcy in 2008.
The most difficult problem I have encountered is that very few machine shops want to hire someone that works off site or telecommutes. They want someone on site that they can "keep under their thumb." They falsely think that they "get their money's worth" this way. I have worked on site for several of my clients over the years. If they only knew how much money they actually wasted by having me sitting around, waiting for a foreman to make a decision or a customer to correct a drawing they would probably commit suicide. Even worse is while I have sat around trying to "look busy", I have watched their employees doing the same. This goes against my ethics, but when you have a family to support, you do what you have to do. If they would have allowed me to work from my home office, during these down times, I would not have been charging them, I would have been doing work for other clients. I still would have made the money I needed to support my family and they would not have been wasting money paying me to sit around waiting. Their loss. Right? Like Forrest Gump's mama always said, "Stupid is as stupid does."
The market for contract CNC programming is small. Many of your clients will not only want you to do the programming, but they will want you to set up their machines and run the parts too. Currently, I only have 2 clients. One in Florida and one in Texas. Ideally, based on how much work these 2 give me, I could make a decent living if I had 10 clients. My "hourly rate" is $40.00. I charge a 2 hour minimum per part program (operation/set up). 2 hours covers most simple parts. I give 1 "re-write" for no charge, unless I obviously screwed something up. In that case, I keep working on it until I get it right. If my client (or their customer) makes enough of a change to a part to classify as a revision (whether they call it that or not) I charge them for it.
I am also an instructor. I am also in negotiation to start a school for machinists here in Dallas, Texas. I intend to teach to the NIMS standards using NTMA teaching materials. I hope to have this school NIMS accredited for Machinist - Level 1 within one year. Our proposed study plan calls for 408 hours. Hope to start our first class November 1.
Don't know if that helps you make a decision or not. But there it is.