Shelter is just like real estate- location,location,location. A space blanket deployed in a rock outcrop or under a fallen log etc is emminently superior to a tent pitched in the open field facing a blizzard. So you pitch your tent under the rock outcrop only to find pole A won't fit into sleeve B because floorplan C doesn't fit into your retreat to begin with. Tarps and their smaller cousins space blankets can be deployed in countless variations, supplement natural material shelters and are emminently packable. Do you have a fragile bottle of medicine? Wrap it in the tarp. Is the dutch oven in your daypack rubbing your shoulders? Pack the tarp close to your spine. You can't afford a siltarp? Niether could Julia Butterfly's ground crew. We used those cheap blue hardware store monstrosities and scrap plywood over a central floor beam. 735 days, including the worst storm in memory is a bit over the 72 hour rescue/survival scenario, is it not? Colour? Buy some reflective tape.