Reusable Parts and Clean Templates

Imagine two practitioners who each finish a client engagement. Both produced useful pieces of work along the way: a data-handling routine, a configuration pattern, and a set of checks they wrote to confirm results. The first practitioner closes the project folder and moves on. The second spends an extra hour pulling the reusable pieces out of the project, tidying them up, and saving them where they can be found again. A year later, which of them can start the next engagement faster?

The source material calls the collection of reusable parts a slice library, and it makes a sharp point about it: the library does not build itself. Someone has to decide to build it, and that decision has to be repeated after every piece of work. This article explains why the library is worth that effort, how the closing routine builds it, and what keeps it usable for the next person who needs it.

The source gives the slice library a different job depending on who is working. For a solo operator or a small shop, the library acts as a moat, a protective barrier that keeps the practice defended. For a larger team, the library acts as a highway, the shared route along which work moves efficiently between people. The two metaphors point to the same underlying asset, but they describe different ways of getting value from it.

Notice what the two roles have in common. In both cases the library is valuable only because it is kept in a usable state. A moat that has not been maintained does little to defend anything, and a highway with no signs or clear lanes does not move traffic well. The source makes this dependence explicit by saying that the library is vital in both settings and that maintaining it takes discipline. The diagram above shows the shared condition beneath both metaphors.

The central claim of the source is that the library grows only through deliberate action. At the end of every engagement, the FDE makes time to do three things in order: extract the reusable parts into a clean template, write a README that lets the next FDE pick the work up, and add the result to the catalog. None of these steps happens automatically as a side effect of doing the project. Each one has to be chosen.

Read the routine as a chain of dependencies. The extraction step produces the raw material. The README step makes that material usable by someone else. The catalog step makes the finished piece findable at all. The only decision point in the source is whether the FDE chooses to run the routine at all, which is why the flowchart shows a branch where the library does not grow. Skipping the routine does not cause an error anywhere; it simply leaves the library unchanged.

The source also says that this discipline is what compounds. Each engagement that ends with an extracted, documented piece leaves the library slightly larger and easier to use, and those small additions accumulate. The benefit does not show up in any single engagement. It shows up in later ones, when a practitioner starts from existing parts instead of from nothing.

To see how the library changes over time, follow a small illustrative library through three engagements. The names and counts below are invented for teaching purposes and are not drawn from the source. Each engagement ends with the same routine: extract the reusable parts, write the README, and add the entry to the catalog.

The README is what lets someone else pick up a part. The source is clear that skipping documentation undermines the library even when the code itself is sound. A template on its own can still exist, but without a README the next FDE has no stated way to pick it up. The catalog entry plays a different role: it is what makes the finished piece findable at all.

In the diagram, the catalog entry is the route by which the next FDE reaches a part, and the README is the explanation the FDE reads before adopting it. The source does not state a fixed reading order, so the ordering shown is an interpretation: findability comes first, and understanding comes once the part has been found.

The source warns that the library is valuable in both settings only when it is kept usable. Skipping the routine on one engagement can look harmless, because nothing breaks at that moment. The loss shows up later, when the next practitioner has less to start from.