maybe they didn't use lining and instead relied on layering.
In a way, lining is an easy way to add another layer of fabric (and hence, insulation) only by adding a single garment. I'm not sure the two are mutually exclusive.
I'm mainly wondering about earlier period garb such as viking, but I like making garb from various periods. Is there a general time that lining was used by?
I can't help with other early cultures, but there's evidence that the at least some Viking Age Norse lined things.
The 'caftan'/coat layer from graves at Birka seems to have been at least partially lined, but it seems the furs that were once taken to be a full lining, are now considered to have been trimming the garment edges.
See: Hägg, I. 1983. "Viking Women's Dress at Birka: A Reconstruction by Archaeological Methods." In Cloth and Clothing in Medieval Europe (Heinemann); 316-350.
Hägg, I. 1986. Die Tracht. [The Dress] In Birka II:2. Systematische Analysen der Gräberfunde (Almqvist and Wiksell International); 51-72.
Linings, believed to be partial instead of full, show up on the apron dress layer from Birka, too. There's more detail here:
I'm not sure about the woollen underdress, but the 11th c. Viborg shirt of linen, with a lined body, shows that it's even possible on layers usually considered to be underwear.
An 11th century linen shirt from Viborg
Do you always line your garb regardless so it will last longer and such?
Personally, I'll line outergarments like coats for warmth, and I've lined an apron dress with linen for wearing with a woollen gown to prevent the layers sticking together. But don't do it as a rule.
Hope that helps!