Answer:
What loses its head every morning only to get it back every night?
Other terms for this handy device include doohicky, doo-dad, and whatchyamacallit.
What has only two words, but thousands of letters?
What starts with an "e" but only has a single letter in it?
I have joy in bringing two together, but darning my existence! My life hangs by a thread, filled with ups, downs and resistance!
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.