When I ordered my WBBB hammock this summer, I bought a tarp for it, but postponed a Top Quilt due to cost and it being summer I didn't need it yet. I did get an UQ but haven't tried it yet because of the warm weather.
I am really looking forward to our Texas Hang next weekend, and it will be my first time using the hammock with temps at night forecast to be in the 50's -- good for a first run to see if I can configure it right without having any drafts. I ordered a TQ but don't know if it will come in before next weekend, so I may be needing to use a sleeping bag as a TQ, but at that temp I should be OK.
I grew up sleeping in a hammock quite a bit, but I grew up in the tropics so never worried about it getting cold at night. Seeing folks here hanging with snow on the ground amazes me and I do want to try to keep camping as the temps drop (I know, here in Texas we don't really have it COLD, but last January on a kayak-camping trip I was quite uncomfortably cold in a tent when it got cold enough there was ice in my kayak the next morning).
Since my UQ is a Yeti torso-length, I'm wondering if I need to also get a full-length one for camping when it is colder, but I'll see how the Yeti does first.