The main reason to find oneself in this dusty town is to go hiking. It's a magical place, partly because of the people one can meet in town who came for the same purpose. I definitely could have stayed a longer amount of time. As it was, and given my time constraints, I think I was there just the perfect amount of time to do every day hike--namely 3 days, 2 nights.
1. the weather is unpredictable, so be prepared to either grit your teeth and do the hike anyway, or be willing to change plans. For instance, my full day there was 'ruined' by rain and wind in the morning, which meant I decided against hiking up to the Lago de los Tres (Fitz Roy). That said, after waiting a few hours reading I was able to go walk all the short hikes (mirador de los condores and aguilas as well as the chorrillo salto) in the afternoon.
2. weather permitting, save Fitz Roy for last. It is such a gorgeous hike, and an overwhelming view, you will want to do it again and perhaps miss the other good hikes. This is principally the Lago Torre. I did it my first afternoon, and in hindsight it was an equally magical experience to the Fitz Roy. Fitz Roy is also a destroying hike for anyone who isn't in pretty decent shape, so build it up by doing the shorter ones first.
3. Do them all! 3 days will do it, and beats sitting around in a hostel-hotel-restaurant instead. Follow a punishing time in town with a few long bus rides (i.e. to Puerto Natales) to recover. This is how my travel agency, Say Hueque, arranged it, and I wouldn't have changed a thing.
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