For me this entirely depends on where I'm going. For urban edc (on my person) I frankly don't bother with redundency in fire or knife, and I don't edc any form of shelter. But in my urban environment I can generally count on being able to get to my vehicle - in which I have what I need to survive 3-4 days easily.

Backpacking or just a walk in the woods is a totally different issue for me. I expect and plan to get lost and have to survive a day or two (heck, I get lost in our city parks!). With this in mind I go for triple redundency in fire making, redundency (two) in knife/multitool, a tiny FAK, a mylar blanket (yes.. I know the objections) and Doug's PSK. And water. I do not care about added weight at all. If the little extra weight were truly a factor, I shouldn't go.