To piggyback off this, hobby machining in general. You can buy a small lathe pretty cheap but add some decent tooling and oh you need a very fancy tool you don’t have? Hand over more cash. You want to make a part that won’t fit in your small beginner lathe? Time to fork out for a bigger more expensive one. Oh a mill would be better for that part? Those kidneys could get a basic mill. Oh you need more fancy tooling for the mill now…