Opportunity costs (doing one thing vs. another) doesn't necessarily have to come down to just money. It can be something like do you decide to go and play some video game instead of studying in which one decides for themselves the relative benefits and costs associated with each. Sometimes it's a combination of the two as it certainly appears to be in Jin's case.
I see the point that you're making, but I have no idea how one could make a calculation that isn't completely hypothetical?
Now Jin has said, at least initially, that he spent a total of about $1100 on the project. Further that it was better than any $1100 speaker out there. Now, I'm not the one saying he came out ahead. He is and to justify, rationalize, figure it out, whatever, he's setting a labor rate of $0/hr. because in part, the time with his Dad is priceless. But I'm not setting $20/hr as the monetary equivalent to time spent with his father. We can factor that out as some sort of intangible to be added after the fact. That number is nothing more than saying, had he been able to work a second part time job for those same amount of hours, what would he have earned? If it's $2800 then add it to the material cost and you get a more realistic cost for the project.
Well, you'd have to make the assumption that if he didn't work on his speakers, he'd have gotten a second job to fill that time. If he wasn't prepared to fill that time with paid work - speakers, or no speakers - that time has no monetary value as I see it. But then, I'm not an economist, so what do I know.
Now, let's say that the total cost was $3900 and he couldn't tell the difference between that and your hypothetical $3000 speakers. Only Jin can make the personal value judgement as to whether that was worth it. But let's say that he consistently picked the $3000 speakers over his. What then? Maybe it's still worth it and maybe he'd do it again because the value to him of time outweighs everything.
This is still assuming that he would have been otherwise employed, if he wasn't working on the speakers. We just can't make that assumption. The only inputs we can objectively measure are the costs of the speaker parts, any tools purchased expressly for the project, electrical power consumed by power tools and lights, etc. Of course, how the Statements fare against any other speaker is something that can be tested. They can be measured under the same conditions as other speakers and a panel of qualified listeners could assess them against the others and then draw some conclusions about relative performance. Until then, we just have his word. He simply can't avoid being biased when he judges the Statements' performance against any other speaker - that's just human nature. But, an independent panel of judges may say he's absolutely right.
Please understand that I'm not taking a stand against DIY no more than putting in a sink yourself instead of hiring a plumber. 'Course, if that sink leaks, and you've chipped the counter top, you just might have to rethink your thought process. If not, your wife will do it for you. It's nothing more than coming up with a more realistic cost of one's speakers.
No. What we do is total up the costs for materials which would include glue, stain, rags, tools such as a router, bits, blades, clamps unless he already had those in his possession. As to labor costs, that depends on the individual because each of us, should we choose, just might be able to find some sort of job after hours commensurate with our respective abilities.
Take the case of a woman who knits a scarf and it takes her 10 hours with material costs being $40. If we arbitrarily assign a $10/hr. labor rate, it cost her $140 to make that scarf. That same scarf, or shall we say a comparable one might cost $60. This DOES NOT MEAN she should abandon knitting because maybe she derives some complex personal satisfaction. Maybe it's time spent with her daughter. Maybe something else. But from a purely economic POV, she is willing to incur an economic loss for her handmade scarf because the other benefits, intangible as they may be, to her compensate for it.
That depends on what the alternatives are and they're not the same for everyone. Nor does it necessarily involve a dollar figure as I illustrated above.
I admit, it's a difficult matter. If you were to search for the terms leisure, opportunity, costs, you'd find there's been papers, studies, and what not published on just this thing. There doesn't seem to be a consensus on how to calculate it but by the same token everyone is not unilaterally assigning zero to it either.
If you've read what I've written, then you'll understand at no time am I telling him or others that what he did wasn't worth it. He's said he thinks his speakers are possibly only bettered by moving up to the 10-15K range. If that's the case, then what is there to object in my assigning a total cost of $3900? If then maybe there were other options worth considering. Work the extra time, if possible, to achieve sonic equivalence and go fishing with your Dad, or a road trip, or any number of things.
I can see where you are coming from, in that there are "costs" over and above the materials used in construction of the speakers. But, the way I see it, only the person involved can make that calculation. Only he can say if he would otherwise be engaged in paid work. Only he can say what the emotional cost is, if he confines himself in his shop and ignores his family. Only he can say he might have gotten more exercise if he wasn't working on the speakers. In other words you or I, or anyone else could add a hypothetical additional cost above the material cost, but it would be meaningless, as we'd be picking figures out of thin air.
