"Anybody have any (true) very spartan tales?"
Its funny how people seem to always get the idea that "spartan" tales might be made up.
Ive never counted how many nights of anything... I only carry a foam pad if I know I cant (reasonably) improvise. My last trip, I was able to gather about 2-3in of mostly dry leaves and laid them down into a roughly body sized nest of common juniper. It took only a few minutes to gather and arrange the leaves and I was absolutely warm, even though it snowed that night. I almost always carry a synthetic sleeping bag or military poncho liner with me, so no tales of daring-do there. I sleep far too cold to mess around with not enough nighttime insulation... though I used to just use a wool blanket back when I was "goin' ta ronny'vou". I rarely carry a bivy sack, and my tarp is a military poncho... which unless rain is a certainty, I usually just wrap around my sleeping bag. It blocks the wind, stops light rain, and acts as all the ground cloth I might need. Ive thought hard about getting a Gatewood cape or a silnylon poncho to drop some ounces, but I haven't yet because I would lose the "improvised bivy" function if I went that way.
I carry a backpack, a sleeping bag, my poncho, some spare clothes (usually just some extra nighttime insulation), my 10 essentials, and few other odds and ends.
Not quite John Muir, but I can honestly say that I carry less (fewer) than anyone I know.