I bought and assembled my first 3d printer kit last summer, a MakerBot Thing-O-Matic (the device in the middle).
Since then, it’s printed the Reprap Prusa Mendel printer (on the left) which I assembled and gives me a bigger build area. Both of those printers have contributed different parts (in ABS and PLA plastics) for the prototype Tantillus printer on the right which is nearly complete and will be ultra portable (possibly even battery operated).
My Thing-O-Matic has also printed dozens of Prusa parts kits which have lead to (hopefully) dozens of other printers coming online as well…and it just keeps going. That doesn’t include the hundreds of (non-printer related) objects all the printers have made as well.
That’s kind of cool when you think about it.