I bought an unknown amount of laceweight yarn on a cone from an op-shop.
I plied it up on a weekend away.
Now to continue the story:
When we got back I finished plying it, counted it and washed it. It comes to 2118 meters of heavy laceweight. more than enough to make a long version of the cardigan I want to make from it.
This picture does not truly capture the beautiful colour this yarn is, a delicate sea green. All in all this was a very satisfying experience, and I'm looking forward to seeing how it knits up.