Naturally, one can't go on a long trip without buying a bunch of stuff. Here are some problems I've had, and the ways I've attempted to solve them by Buying Stuff.
Warning 1: I'm not endorsing any of this stuff; I haven't tried it yet. I'll let you know how it flies in Kazakhstan.
Warning 2: suuuper whiteness ahead.
I want a pair that will be comfortable anywhere: hot places, cold places, hiking trails, and cities. And ideally I wouldn't look too North-Faced-out. Hiking shoes are out because they're heavy and miserable in hot places; regular sneakers or street shoes get wet and make your feet hurt after a while; fancy shoes don't do well outside cities. (I don't want to look too businessman either.)
Solution: Vivo Barefoot Miles M. I'm in with this whole barefoot fad/truth, so I'll let my feet adapt to thin shoes rather than lock them in heavy hiking boots. Plus, they're water resistant, and they look nice.
I have to bring sandals, right? I mean, South India? Socks are the worst. But I don't want to lug my clunky Chacos. Also, I'll be adapted to barefootness. (seriously, look up barefoot running; I won't argue about it here, but I'm moderately convinced.)
Solution: Luna Sandals. These huarache-style sandals are 6mm thick, weigh about nothing, and are kind of fun to wear.
I don't want to get rained on, but I don't want to bring a big heavy jacket.
Solution: Montane "marathon" jacket. It literally stuffs into the size of an apple. It is literally just a windbreaker, so no warmth, but I'll deal with that otherwise.
Hoo boy, this is a can of worms. You can't just drink the water in India (among others). If you're going for a short time, you can buy bottled water. But if I were to drink(/teethbrush/etc) 2L/day for a year, that's over 700L of water, which would be probably 500-1400 little bottles. And it's about more than carbon footprint (he says, flying across the world); I'm going to some pretty tourist-ravaged places (e.g. Nepal) and I don't want to throw any more bottles into a big Nepali pile than I have to.
But naturally, you can't just walk into REI and buy a filter! First, you have to decide whether you want to be protected from bacteria and big stuff (for which you just need a filter) or bacteria, big stuff, and viruses (for which you need chemicals or a purifier). I think that I need virus protection; the only guideline I've heard on that is that there are viruses in the water in poor countries, and generally not in the US.
So what's in the market? There are camping-style filter/purifiers, which are big and require pumping, which I cannot do at a table. Some of the filters have a nice bottley form factor (I figure I'll be carrying a water bottle anyway, so no extra space there); you just put water in there and drink out of them. Most of the bottley ones are just filters, although there's this Katadyn purifier, but that only lasts for 100L, and I don't bank on finding replacement cartridges.
I was going to get a Steripen. It's a little UV light which you stick in your bottle and stir, and it kills all the viruses and bacteria and everything. The obvious downside is that it requires batteries, and the batteries only last for 100L tops, so I'd need to bring rechargeables (standard alkaline batteries don't work), and a charger, and then deal with finding a plug adapter for the charger... ugh! Plus, if the REI reviews are right, they're not super reliable.
But then I found the Drinksafe Eco: a purifier in a bottle that lasts for 1600L! Guess that UK technology hasn't percolated over here? Well, whatever: I've got one shipping to me as we speak. Excited about this.