I think it was Doyle, at VPX, who talked about economics in worldbuilding. That artefacts exist because somebody made them, and somebody paid for them, and somebody transported them to the place they appear. And that you have to consider these factors. Not explain them on the page, as you know, Bob, but that you could explain them if you had to, and it wouldn't contradict what was written.
One of my gripes, when reading fantasy, particularly fantasy set in a pre-industrial world, is orphan artefacts. In Shannon Hale's book, The Goose Girl, set in a kingdom that I'd say approximates 15th-16th c. Europe, one character refers to another kicking a bucket into a crumpled lump of tin. So, there's sheet-metal technology here? Available to peasants living in the woods, but not to anyone else. Another peasant woman knits endless sweaters with metal knitting needles. Yep. Not wood, or bone. Steel. Wire-drawing is not elsewhere referred to. I must suppose that the peasant women are secretly running foundries and rolling mills in those deep forests, cunning vixens that they are.
I should admit that I enjoyed The Goose Girl (the original's about 3d on my list of favourite fairy tales, mostly for the oracular horse's head and the talismanic blood-spotted napkin), and I'm looking forward to reading Hale's Book of a Thousand Days.
But she also gives me the opportunity to gripe about another issue in worldbuilding: work. Not that life was unremitting toil in the pre-industrial world--read the complaints about how the number of church holidays in medieval Europe meant the peasantry weren't getting enough done for their masters--but that people, including children, worked hard and worked long hours. Hale has her goose-girl let off from herding the geese out to the fields because ... because it's raining. So she stays inside with the other servants, none of whom are doing anything much, because it's raining.
My mother used to say, "You're not made of sugar, you won't melt." I imagine the overseer of castle servants might say something a bit harsher. Certainly the geese won't mind the rain.
This is by way of preface to linking you to two excellent essays about getting things right (if historical) or believable (if fantasy):
Writing Backwards: Modern Models in Historical Fiction, an essay by Anne Scott MacLeod in The Horn Book (a source of excellent essays). This one addresses the pernicious 'character with 20th c. worldview dropped into historical setting', discussed elsewhere (I'll add other links if I find them--I know they exist).
Competency and work, one of the Fantasy Rants by the wonderful Limyaael, on how the people who do the work can be just as / more interesting as the Designated Heroes.
UK 08 Lincoln, continued. Lucia and I stayed at the Orchard Guest House, which I can recommend as being comfortable and clean, with a fine view over the town (Lincolnshire is flat fens. There's one hill, so they built the castle and the cathedral on it, presumably to avoid sinking and to keep the population fit.) and easy walking distance to the Castle and Cathedral, and not too far from the Strait and Steep Hill.
We had a wander around, and I tried to take photos of the ecclesiastical architecture but it was difficult to keep my hands steady. I also took pictures of trees, because England! Trees!
On the drive down I'd noticed a number of trees with tangly clumps of nests in them, and my brain had said, smugly, 'rookeries'.
Shut up, brain, I replied, what do you know about rooks? Have you even seen one for sure?
"What are those clumpy nests?" I asked at lunch.
"Rookeries," said everyone.
'Ha, told you,' said my brain, even smugger.
We had supper at Brown's Pie Shop, though we weren't able to get a table in the haunted basement, it being booked for some family do. We were able to nip downstairs as we left, and to call gently for the ghost, "Humphrey, Humphrey?" but there was no response. The food was luscious. I had steak & kidney pie, Lucia had cheese pie. Food in UK restaurants has improved immeasurably since our dreadful experiences 20 years ago.
A couple of pictures that warn of what is to come:
A tree that I think is cool. Possibly a plane tree.
A bit of stonework that I think is cool, from the gate by the cathedral.