{"Completely"}self sufficient? Took me about 5 years. From learning what kind of tree to cut the wood from for bows, another kind for arrows, gathering feathers and learning how to make bowstrings from nettle fibers, then making broadheads from whatever steel banding I could find. And then learning how to make everything work.... Had it all figured out by the time I was 10 and got my Boy Scout archery merit badge.

Then I started buying store bought stuff when a couple of stores in my town started carrying ready made arrows, and even bows! Thought it was pretty cool for a long time, but I've never been quite that self sufficient everagain.