In a world where resources are not especially scarce, and where manufactured technology is the norm, a practitioner of some skill is still expected to go out and scavenge the materials and parts to hand-make their own tools of the trade. This isn't merely a case of making do, but rather, the expected way to do things.
It may be implied that toolmakers have some inherent connection with the tools they make, or it could be a cultural expectation, or it could be a part of the testing process to demonstrate mastery, with a presumption that the master has to know how the tool works.
Nonetheless, if you see a master at using some tool or weapon pull out their tool/weapon of choice, they probably were the one to build it, and probably had to dig up all the materials and refine them too, no matter how easy it would be to just go down the street and order one.
By making an object, it is imagined that you know that one object more intimately than someone who merely purchased off the rack, and were also able to work whatever tiny adjustments you prefer into the manufacture; alternately, the naturalism of crafting a tool by hand appeals to the "Harmony" side of a Harmony Versus Discipline
- While Iron Man forging his first power armor in a cave with primitive tools does not count, Steel, one of the Superman types to appear immediately after The Death of Superman forged his suit of power armor in the very same way - however, he was a techie living in a major city and working out of his basement, and probably could have arranged some better tools than a hammer and anvil.
- Star Wars: Technology abounds everywhere, and yet the Jedi are asked to acquire all of the parts for and assemble their own lightsaber by hand from scavenged parts they find over their travels.
- The Natural: At the beginning of the movie, lightning strikes an oak tree outside the family home. Obviously, the thing to do is to turn the wood into a regulation baseball bat and use it to start a career as a professional baseball player..
- In The Good, the Bad and the Ugly Tuco (The Ugly) built his own revolver by taking bit and pieces from a bunch of different guns in a gun store. None of that gun store's best ones was good enough for him.
- The Panzerbjorne in His Dark Materials forge their own armour from "sky-iron". This is important, as they consider their personal suit of armour to house their soul.
- All The Weyrs Of Pern: AIVAS has each member of the team dissecting Thread make their own tools, despite the presence of a craft guild that could have easily provided enough tools for the team.
- Two short stories by Richard Bach describe a hidden city which teaches the best pilots in the world. Initiates there, among other things, are required to build their own airplanes to train in, starting from primitive gliders and progressing upward through jet aircraft.
- In the book Iron Council, Judah becomes contemptuous of a military golem-crater when she unfolds and animates a pre-fabricated leather-and-metal golem to sic on his allies. Judah, himself, always makes golems from materials found on-site.
- Shadowrun. In early editions, "real" deckers built their own cyberdecks from scratch by creating their own deck components. Deckers that bought standard parts to create their deck (or, even worse, a commercial cyberdeck) were looked down upon.
- The Simpsons spoofs The Natural in "Homer at the Bat" when Homer has a homemade bat he uses to play softball. "Something told me this was a very special, very magical piece of wood...that I could make a bat out of." Once the other members of his team see him hit homer after homer they make their own bats too, out of things such as piano legs and artificial legs.
- In the martial art Capoeira, teachers are expected to learn to build their own musical instruments. This only grows silly when taken to the point where they are expected to burn/cut the wires out of radial tires as strings, despite the fact that piano wire works just as well and lasts longer (the wires are often removed by burning, which makes the wire brittle and faster to break).
- Some archers today prefer "Primitive" bows, which they make themself. This is said to be more rewarding and enjoyable than learning with the more predictable manufactured bows.