Six months was a long time to spend in South America, and it felt even longer.

But on my return none of the fundamental reasons that drove my departure had changed– I was still young, relatively unburdened with responsibilities, and still had the means to see more of the fascinating world that exists beyond our shores. Furthermore, I quite enjoyed my South American adventures.

There’s a steep opportunity cost to extended travel. There’s the companies not founded, the relationships not pursued, and the money not earned. In real terms, six months in South America cost barely more than six months of typical US living expenses, but the foregone earnings are significant.

But there’s another opportunity cost that’s almost invisible to us in our twenties– our youth and health and perspective.

I didn’t meet many travelers past their thirties, but those I did unanimously expressed a wish that they’d traveled more (circumstances permitting)  when they’d been younger, fitter, and less susceptible to hangovers.

At 28 I’m near or just past my biological prime. Granted, healthy living enables some 50-year-olds to kick some 20-year-olds’ asses, but every year it becomes harder to outrun our biology.

Energy and lack of family commitments make our twenties uniquely suitable for pulling insane hours to launch our careers into stable orbits– or enjoying the rigors and rewards of traveling to some of the world’s more inaccessible locales.

That’s why I’ve spent the last month and a bundle at REI outfitting myself for a jaunt north of the Arctic Circle to Norway’s Lofoten Islands. I’ve always wanted to see the fjords, and 22 hours of sunlight sounds pretty cool.  The working world can wait a little longer.

Of course, the cheapest flights to Europe are to Dublin, so I’ll need to stay a while to check out Ireland while I happen to be there.

…and some friends I met in Argentina are going to be partying in Barcelona, so I’ll have to make a quick detour to visit them.

…and after hauling all that camping gear to Norway, I’d be remiss if I didn’t walk some of the other great treks of Europe– in Switzerland, Scotland, or elsewhere.

…and while I’m in the neighborhood, I might as well take in the accumulated art, architecture, and cultural treasures of the past 2,500 years.

…and there’s Spain. It would be a shame to let my Spanish get rusty, and I’m curious to follow Latin American history and culture to its source.

So I’m off again with a one way ticket and open itinerary, not to return until I find a lost Viking treasure horde, run out of contact lenses, or my desire to build on the world exceeds my interest in experiencing it