this horse is undoubtedly dead... but like michael jackson I will 'beat it' some more.
I get bizmans point fully and I would assume everyone on this forum is here because they find building to have intrinsic value that is "worth it" for them. To say that there is no point in considering your time as part of the value of that instrument unless you are building to sell it - well, we'll just have to agree to disagree.
The orig focus of this thread is what is the "REAL" cost of building a guitar. IMO the most expensive thing you put into it, even as a hobbyist, is your time. After all, you only have so much on this earth. You could have spent the time drinking beer or sleeping and that has value as well. You could have spent the time with your wife watching movies. Could have spent the time shooting sporting clays or making music. You could have spent the time bullspitting with friends online (wait... ). The parts/materials... those are just expenses... the real cost is your life.
If I want to compare the value of a guitar I just built to what I could buy from someone else... sure I have to factor in the amount of fun I had building it, the joy I get from showing it to someone and saying "I built that with my own two hands", the amount of relaxation it added to my life by forcing me to focus on it instead of what is coming down the pipe at work... but also the time I spent on it, the risk I took potentially lopping off a finger, the potential of ruining my back to the point I can't stand straight anymore, the reality of a wenge sliver... and least of all: the money it cost.
Surely you would agree that the "REAL VALUE" is not just the money you could sell it for? So logically the "REAL COST" is not only the money you put into it but all your materials -including time.