Overview
The basic observation is that, if we think of life as an optimization problem, then redefining the search space is much more important than making local optimizations; as a fact of human psychology it's hard to consciously focus on both; but we can implicitly get away with doing both by creating mental triggers for when local optimizations are likely to be particularly effective to think about, and by structuring things so that many local optimizations get made automatically.
Introduction
If you have been to one of the Rationality Minicamps or certain other CFAR events, you may have had the privilege to attend one of Anna Salamon's excellent classes on microeconomics (despite the title of the post, I am being sincere here; you really should attend them if you haven't already). There is too much content to briefly summarize, but essentially "microeconomics" in this context means applying basic microeconomic concepts like marginal value, value of information, etc. to everyday life. For example, if you spend 30 seconds brushing your teeth each day, then spending five minutes to think of something else to do at the same time (like stretching) will save you 3 hours a year, which is a great investment! (There are some caveats to this calculation, but I'm glossing over them as they aren't relevant to the post.)
And indeed, spending 5 minutes (once) to save 3 hours (every year) is almost tautologically a good investment. Now that I've brought up this example, and assuming you value your time, you should probably actually go through this exercise (or just use the stretching suggestion).
The Problem
I intend to argue against something similar to this but subtly different. Basically, while any given trade such as the one above is good, I think it is a mistake to systematically search for such trades. Note that I also don't want to argue that you should never search for such trades. If you're about to buy a car you should almost certainly put a lot of microeconomic optimization into it, and if you can find things that improve your overall work efficiency substantially, then you are winning big-time. But I worry that, sometimes, the wrong lesson is drawn from these microeconomics examples (or cognitive bias examples, or any other rationality skill), namely that X is suboptimal by default and we should go out looking for places to optimize X.
The reason I think this is wrong is because it aims much too low --- if you really want to save the world, then your average thought needs to be good enough to save two human lives [source: the average human lives only 3 billion seconds]. Even if each individual optimization you make ends up adding to the amount of time you have, the overall process of concentrating your attention on such optimizations makes you less likely to think other thoughts that would be far more valuable. Perhaps another way of putting this is that, even if each small optimization helps you a little bit, the time it takes to think up such optimizations actually makes you lose out --- however, I don't think this is actually it, I think it has more to do with forming mental habits, where you want to form the mental habit of making huge optimizations rather than small optimizations.
The Solution
What I think people should be more concerned with than micro is what I'll refer to as macro --- the overall structure of the search space (in this case the structure of your life and how you think) --- as opposed to making local optimizations within a fixed structure. For instance, becoming an atheist; or realizing that social skills are both trainable and highly instrumentally useful; or learning to visualize the steps towards a goal; or learning to code; or finding a group of allies that you didn't previously realize existed; these are all examples of what I'd call "macro" optimizations that are the sorts of things we should be looking for. (I should note that a lot of "macro" skills were also covered in Anna's microeconomics units.)
I also continue to think that there is a clear place for micro-level skills, as well. The key is to incorporate them into your thought process, both at the level of creating triggers to explicitly call micro-level optimization routines when they are likely to be helpful, and at the level of restructuring your thought process to automatically be more likely to make good decisions by default. For instance, the lesson I drew from Eliezer's posts on cognitive biases were not that we should go learn about all the different cognitive biases, but that we should develop habits of thought that will automatically notice and decrease the effects of such biases. Then, for a couple of the more pernicious ones like trivial inconveniences, I further added specific alarm bells in my head to watch out for those, but only because I noticed that avoiding trivial inconveniences was routinely harming me.
Conclusion
I'm not sure how good of a job I've done of explaining what I wanted to (it's still not entirely clear in my own head), so I invite your thoughts and feedback. I'd be particularly grateful if someone wiser than me (I'm looking at you, Critch / Wei / Yvain) could figure out what this post was trying to say and then write that instead!
I completely agree that the two perspectives can be integrated (I even spend a paragraph discussing how, the one starting with "I also continue to think there is a place for micro-level skills..."). However, it is possible to micro-optimize successfully and still lose, but this is much less true of macro-optimization, so I actually do think it makes sense to present one as better than the other.
(There is a separate danger in macro-optimization, which is that it is easier to deceive yourself into thinking that a bad or neutral optimization is actually a good one. For classical examples, take going on diet X, or training yourself to sleep for only 5 hours each night.)
I think it's about more than the scope of the decision problem. The techniques you use to optimize at the macro-level are fundamentally different and I really do mean in many cases "change the structure of the search space". For many people, reading the Sequences had such an effect; or going to college; for me one of the most salient recent examples was working at Dropbox for the summer, which completely changed the way that I approached writing code. I didn't decide to work there due to the output of any explicit optimization, though. It was "this has many characteristics in common with the sort of thing that will end up changing my life; so, even though I can't give any specific mechanism as to how it will actually do that, I'm going to work there anyways".
Re: Toyota; the difference between Toyota and a human is that Toyota makes millions of cars each year, so even saving 1 penny on each car manufactured is worth tens of thousands of dollars to the company.
It's not clear to me that this is the case. The parts of the problem that are hardest change, but the problems are fundamentally similar in a deep way. I will agree that the training to improve macro-level optimizations and the training to improve micro-level optimizations have different focuses, and am working on a post that will be relevant to the former.