What's six months' worth of bug spray?

Getting ready for six months on the road means a lot of little packing debates. What will be valuable enough to us, and difficult enough to get in other countries, that it's worth adding to the load on our backs? Experienced travelers will say "almost nothing" -- the idea being that most things we'll want, we'll be able to find, and those things we can't find, it'll be good for us to learn to live without. "Too true!" I say to myself every day or so, blithely ignoring a lifetime's worth of fussy materialism. "Two t-shirts and a passport for me!"

Except. There are also experienced travelers who helpfully share the things they couldn't have lived without, or really wished they'd had. A sleeping-bag liner for when sheets are unavailable or suspicious-looking. A headlamp, not just handy when one goes camping, but also when there's a power outage. Dental floss. And for every person who says "Of course you can get dental floss where you're going," there's another who delicately explains that we shouldn't expect other cities to supply the Western comforts we're accustomed to and maybe we should quit imposing our dental expectations on the rest of the world.

And then there are edge cases. Like: Kevin and I each have really big feet. We are borderline flipper people, who have enough trouble finding shoes we like even in the consumer paradise of San Francisco. If this sounds to you like I'm asking permission to pack more shoes -- well, then, I concede that you have met me. But on one trip to Paris a couple of years ago I walked holes in the soles of one of my three pairs of shoes, and a few Parisian salesladies were so sadistically, orgasimically happy to tell me how unavailable my shoe size was in their lovely city that the next time I go to Paris I plan to wear hot pink Crocs just to spite them. Is it worth packing an extra pair of shoes -- even though they take up so much space -- in case our other ones fall apart?

Or, OK, here's another one. I use this special kind of contact lens solution that's basically hydrogen peroxide. It's a pain, but using it put an end to a year's worth of nasty eye infections, so I'm attached to it. It may not be easy or possible to find this stuff in the developing world. But carrying six months' worth of contact solution feels perilously close to packing six months' worth of meals.

Fortunately, the scarcity of time and space will solve this problem. We will run out of minutes in which to have these debates, and backpack space in which to wedge any hotly debated items. Until then, though, I'll be over here determining how many days a one-ounce bottle of DEET is likely to last us.