personally, i watch the caravan for metal ORE blocks, like "native gold block" and buy them all.
they dont get used for normal jobs(as far as i have observed) but they DO get used for moods, where the high item value of the metal ore block helps you end up with higher value artifacts
I can't think of any job that uses Blocks where you don't get to select the block you use. As far as I know, Mason's and Craftsdwarf's workshops don't make anything out of blocks, so they're for constructions or buildings (either Wells and workshops that require them, or any other building if you like)
So it's not just ore blocks that are completley safe. I regularly buy out the block supply of human and dwarven caravans to get interesting colored constructions in fortresses choked by diorite.
that's a good point, i prefer when i can color code levers and what they link to, (microline lever - microline bridge) and so forth
i remember a point long ago where crafting took rocks or blocks at random, so someone reccomended i turn all stone into blocks to save space.
it seemed like pointless work to me so i didnt bother, i guess it got changed somewhere down the line
also i buy up supplies of things i dont intend to use, and just stash them out of the way somewhere.
a few zinc bars here, some silk/wool cloth there, dosnt cost too much, and saves lots of panic when moods arrive
(thread can sometimes be VERY cheap, and eventually gets made into cloth)
using DFhack to watch when moods happen, a few of those moods didnt make lead things because it was closest, occasionally the dwarf will specifically demand LEAD(Urist: stop making(possession) lead swords damnit)
stone demand are usually for boulders, but occationally blocks, just as gem demands sometimes want cut, and sometimes they insist on raw
in many cases they want some of both
edit: when i think of it yes, these days it's mostly safe from me, as i'm REALLY unlikely to decide to use those odd ore blocks for bridges and things like that
