Thanks, it will take me a while to get through all this. There are some great comments in there.
You could probably do an analysis looking at the expected utility in terms of social benefits (people seeing you as well-dressed or fashionable), or performance of the clothing (sports clothing, jeans, work boots), depending on what you wear and do.
In terms of clothing minimalism, it probably depends on your friends and work environment. Many people seem to have multiple similar-looking work outfits, so that they don't have to worry too much about changing their appearance regularly, and others have room to imagine any number of identical items of clothing in the wardrobe at home. Without evidence to the contrary people tend to expect you to have a similar amount of clothing as they themselves do.
A good tactic is to keep a number of discernably unique and stylish clothing items that you do not wear often at all. These can be rotated for social occasions, so that you aren't seen to be wearing the same thing twice in recent succession. This seems to be all most people look for, although it depends on your associates.
Personally I wear whatever seems comfortable and appropriate, making sure to wash most clothing items after one day of use, and thinking about the social implications of being seen wearing whatever I am wearing. The social implication of wearing the same thing for multiple days is that you are dirty and smelly. In my experience as long as you keep clean and presentable, and are seen to have multiple different clothing items, most people don't worry about it, but this may be highly dependant on your local culture.
Regarding things wearing out at the same time - well, even if you use them as evenly as possible there should be more than enough randomness in daily usage to mean things wear out at different times. Even if you buy two identical shirts, they won't get the exact same treatment, leading to an increasing difference in the number of wears before each becomes unusable. (see "Random Walk" problems for an interesting mathematical treatment of a similar concept)
Regarding rotation making things last longer - I think it's fine to think of it as a fixed (but unknowable) number of uses before something wears out. So no matter how you rotate your clothes, each item should have the same base value as it would have otherwise. Thus individual day-to-day changes in clothing (which items are more relevant to the current day's activities) are probably much more important.
One last unmentioned point - clothes sitting at the bottom of a drawer can be easily forgotten. It can be good to upend your drawers every once in a while just to make sure you haven't forgotten any hidden gems. Or, err, moth-eaten horror stories (although it's been a while since this happened to me).
Which is why I didn't use the word "justice".
True, it would only make a valid argument if there were some swing voters who were more concerned with fairness than with supporting the power structure of the nobility, which is unlikely.
Judging by Fudge and Umbridge's demeanor, the voters might put more weight on the words of the Boy Who Lived than on those of Dumbledore, especially as Dumbledore wasn't phrasing his arguments in such a way as to appeal to the parts of the audience who didn't already support him.
I agree with your point about it making a poor climax though. I think it's quite unlikely for this reason, but still like the idea of Harry suddenly gaining super-lawyer powers :).
I was referring to the Groundhog Day incident. Harry probably isn't aware of it, but could come across it by asking simple questions of Hermione like "why were you so angry that day of the battle?". Hermione seems aware that she is missing memories here, due to her "lost track of time" statement to Susan.
Thinking of what Draco might have done to her and then obliviated seems a reasonable explanation for her anger towards him during the battle, and perhaps why she can believe that she did attempt to murder him.
Hagrid's story seems to be unchanged, and Harry is aware of it - he was told he was responsible for getting the conviction overturned and the wand returned. The point is more that Lucius Malfoy doesn't directly control the Wizengamot. His main tool at this trial seems to be rhetoric, drumming up righteous indignation and playing the part of the aggrieved Noble. If Harry stops focusing on Lucius and in stead focuses on the individual voters, he can find arguments to sway different sections.
Hagrid's case sets a precedent which makes it obvious the Wizengamot is playing to a double-standard in this case, but he would certainly have to come up with more arguments. Another point he could make is that Hermione had no motive. Another is that her behaviour before the event was completely out of character. He has Hermione right there, and veritaserum on hand, so if he asked her the right questions under veritaserum he could probably find out about the huge chunk of missing time she has in her memory - good evidence that she was psychologically manipulated.
Has anyone suggested Harry simply giving a long impassioned plea, thus acting as Hermione's missing lawyer? He might be able to sway enough of the voters if he proposes a satisfactory lesser punishment (and passes a rhetoric and/or sophistry skill check). Hagrid was convicted of murder in Hogwarts, and his punishment was having his wand snapped and being expelled.
It seems that almost all of the studied phenomena had outcomes determined by other people's emotional responses (presidential primary, idol competition, stock market performance, movie success). These would be expected to correlate with the subjects' emotional responses, as they are likely similar.
This was noted briefly in the paper, but seemed to be largely ignored in the conclusions.
Although the weather study does support the hypothesis, it is a somewhat unfair example, as there is little to go on other than feelings without access to complicated simulation software.
I do believe the fundamental point has validity, but the paper does not seem to support it to anywhere near the level that is implied.
A concrete example of caveats being ignored, from the conclusion:
"The fact that this phenomenon was observed in eight different studies and with a variety of prediction contexts suggests that this emotional oracle effect is a reliable and generalizable phenomenon."
I tend to agree with you about rehabilitation being the primary requirement. I've also found that many people desire retribution first and foremost.
It seemed strange that civil service wasn't mentioned in the article. In my country it is quite common as a minor punishment. Undesirable jobs such as cleaning of public areas are at once highly visible (people can see that they are unpleasant, and that punishment is being carried out) and rehabilitative (a work ethic must be developed to carry out the sentence). Even this, however, is hard to contemplate, as it smells like slavery.
I wonder what other options there may be that are simply hard to table, but obvious in retrospect.
That linked discussion on capital punishment is interesting, thank you :).