[grinich]

On traditional launch vehicles, yes. Shuttle was definitely this way. And I'm sure SpaceX will initially do a complete disassemble and inspection to gather more data about the wear and tear.

But the Merlin engines have been designed from the start to be reusable and dependably reignitable, whether at sea level or upper atmosphere. They're pretty amazing-- essentially the pinnacle of +50 years of engine design. Tom Mueller is a huge badass. :) http://en.wikipedia.org/wiki/Merlin_(rocket_engine)

And check out that bad boy roar: http://www.youtube.com/watch?v=wkdReoxGHG8

I don't have a link on hand, but Elon has said multiple times that the majority cost of the Falcon-9 is the raw material. One of the reasons they've been able to drop the price significantly is by using more efficient manufacturing techniques, requiring less material and creating less waste. (e.g. stir-friction welding)

It's also worth noting that Falcon-9 can still complete a mission with one (and perhaps two?) engine failures, which gives quite a more comfortable margin of error. There's a big difference between "perfect" and "near perfect" when it comes to engineering these things. ;)