I don’t use them, but I have considered the idea. It seems very practical and useful to be able to print off a part whenever you need it. Only downside, is that I bet you’d need a really powerful 3D printer that works with metals.
I regularly use my bike for commute, so i use currently available model in the market. So getting spares is easy for me. 3D printed parts would be actually costlier than actual spares. But it’s still a great idea though.
Yes, you can. But am not sure whether the Printed part is durable as the original spares. In my opinion home 3D printers won’t be able to create spares to support a bike. Industrial 3D printers might, but not sure about that.