Before our last trip to India I purchased 2 pairs of "Ex Officio" underpants, which came with a slogan that went something like "17 countries, 45 days, one pair of underpants". The company makes products of light, quick drying material, and the idea is that you can wash them and wring them out each night and put on a fresh, sweet-smelling pair every morning.
So indeed, when we went to Tamil Nadu for a month, I took along just two pairs (sorry, couldn't get it down to one!). I washed them out each evening and by afternoon of the next day they were dry, usually. It needs to be mentioned that the coastal regions of that part of India have a dank tropical climate and even for there, there was an unusual amount of rain last August. Sometimes it took days to dry a normal load of laundry, and the climate makes you want to change your clothes three times a day. So it was a fairly good test of Ex Officio underwear. On the other hand, my wife succeeded more or less as well to wash and dry her own less-pretentious underwear, since in India it is considered impolite to give one's bloomers to the hotel staff or dhobi.
Last weekend, I did my laundry at home, and it came out to three washing-machine loads. In Israel's dry summer climate, you put laundry out on the line and it's dry within a couple of hours. But Dorit commented on the quantity of laundry that I manage to produce in a couple of weeks and this got me thinking. Why not do the same as we did in India? So now, for the last few days, when I get into the shower, I also soak my socks, underwear and a shirt,then rinse it out and hang it on the line. It takes a couple of minutes. I put on the previous days set, after ironing my shirt. I figure in this way I can cut down drastically on the amount of clothes I need, and not have three loads of laundry to hang and dry every second week.
Also, I should mention that light cotton shirts dry even quicker than my fancy-pants hi-tech Ex Officio underwear. I have a couple of hand-spun shirts from Delhi's Gandhi Ashram that I love.