I think it's interesting that in all the episodes of Survivorman I've ever seen he always sets snares but I've never once seen him catch anything. Of course, I only see the show sporadically on youtube so I haven't see them all or anything. Most situations where you're lost you probably will be found within a few days; in extremely remote areas you'd be wise to carry more gear. Depending on the circumstances and the space I have, I'll normally have some snacks on me. It's for moral as much as anything. If you can build a fire, keep the rain off you and stay hydrated I'd say you're in good shape for a few days. For a 3 day kit almost anything else borders on being a luxury. Of course, that's excepting medical supplies. And you can never count on being found in X amount of days.