> Which will typically get you arrested, unless you know how to do it right.

I don't think there are laws against trying to shoe your own horse and doing it badly if that's what you mean.

I'm a horse owner who works as a software engineer for a living, and I'm so enraged by how much I have to pay the farrier and other horse-related tradespeople that it has very seriously crossed my mind, many times, to take the other side of the trade and give up software engineering to become a farrier.

It's the horse owners who are burning money, not the professionals.

I used to live in Munich, which is an insanely expensive city to live in (with only mildly higher income levels than the rest of Germany), and it has a shortage of farriers. Farriers commute hundreds of kilometers to work here, and still horse owners struggle to find them. If you set up shop there as a farrier, your books will be full in no time. Marketing & Sales? Screw that. Horse people all talk amongst each other and when there's a new farrier in town, word gets around like wildfire. Admin overhead? Nope! The way it used to work in my old stables, one of the horse owners would painstakingly coordinate timeslots with ten other horse owners in the same stable to keep a farrier busy for a day. All they have to do is show up, shoe 10 horses (they don't even have to do that if they have apprentices), and take home maybe €2000 in revenue for a day's work.

That revenue is all cash, of course. Report some of it for income tax (how much is basically up to you), and use the rest in the "informal economy" paying cash to other tradespeople to work on your house on weekends (who, in turn, do the same). If the ministry of finance knocks on your door, asking about this house that you suddenly own debt-free that seemed to have come out of nowhere, you've just been busy at work there by yourself, they can't prove otherwise.

That was a joke about stabbing horses with nails. OP did not say anything about hooves, thus illustrating the point that there are critical details a pro would know.

...ah, okay. Well what I was reacting to was the fact that stabbing your horse with nails is what will actually happen if you try to shoe your own horse and you do it badly, as the inner part of the hoof is "alive" just like other parts of the body and can definitely not accommodate any nails. So the difference between stabbing your horse with a nail and putting the nail where it belongs is something like 5mm, and you have to hit that while the horse (which may be 10x your weight) won't hold still. If it weren't for that minor detail, everybody would just shoe their own horse.

But you probably won't get arrested for attempting this and getting it wrong.

If you have a well-behaved horse and you take a course, like they have in those trade schools in the U.S., where they give you a hoof from a cadaver and just let you practice driving a nail into it 100 times, and then you do it a dozen times while getting feedback from a pro, then it seems quite doable. But those courses don't even exist in Germany, as the trade is that keen on preventing these kinds of skills from becoming too widespread.