How to Build Reusable Systems Across Projects

Building reusable systems—general systems you can reuse across projects—can save significant time on future projects, but only if they're genuinely reusable and worth the extra design cost of making them general. Building reusable systems for the things you'll genuinely reuse, designed to be general and decoupled, is what makes them pay off across projects rather than being wasted effort.

Build reusable systems for things you'll genuinely reuse

Reusable systems save time on future projects by letting you reuse a well-built system instead of rebuilding it, but making a system reusable costs extra design effort (designing it to be general and decoupled rather than specific to one project), so it's only worth it for things you'll genuinely reuse. Building reusable systems for things you'll genuinely reuse means investing the extra design cost of reusability only for the systems you'll actually reuse across projects—the common systems you'll need in multiple projects (input handling, save systems, UI frameworks, or whatever you commonly need)—because for these, the reuse across projects pays back the extra design cost, while for one-off systems specific to a single project, the extra cost of reusability is wasted (you won't reuse it). Identifying the systems you'll genuinely reuse—the common needs across your projects—and building those as reusable systems is what makes the reusability investment pay off, while making one-off systems reusable wastes the extra design effort. Building reusable systems for things you'll genuinely reuse—the common cross-project needs, not one-off systems—is the foundation of reusable systems paying off, because the reuse is what justifies the extra design cost, so reusability is worth it only for what you'll actually reuse.

Design them general and decoupled to be genuinely reusable. For a reusable system to actually be reusable, it must be designed general and decoupled—genuinely reusable, not tied to one project. Designing general means the system handles the general case, not just one project's specific needs—designed flexibly enough to work across the different projects you'll reuse it in, rather than hardcoded to one project's specifics—so it's actually reusable in other projects. A system designed for one project's specifics isn't reusable (it doesn't fit other projects), while one designed general (handling the common case flexibly) is reusable across projects. Designing decoupled means the system isn't tightly coupled to one project's other systems—it's decoupled enough to be lifted out and used in another project without dragging along dependencies on the original project's specifics—so it can actually be reused independently. A system tightly coupled to one project's other systems isn't reusable (you can't extract it cleanly), while a decoupled system (independent, with clean interfaces) can be reused in other projects. Designing reusable systems general (handling the common case flexibly) and decoupled (independent and extractable) is what makes them genuinely reusable, actually usable across projects rather than tied to one. This connects to the principles of boundaries and decoupling: a reusable system needs clear boundaries and decoupling to be extractable and reusable. Combining building reusable systems for things you'll genuinely reuse (investing the reusability cost only for what you'll actually reuse) with designing them general and decoupled (making them genuinely reusable across projects) is what makes reusable systems pay off—reusable systems for your genuine cross-project needs, designed general and decoupled to be actually reusable, which saves time on future projects. Building reusable systems this way—for genuine reuse, designed general and decoupled—is what makes them a worthwhile investment that pays off across projects, rather than the wasted effort of making one-off or non-reusable systems labelled reusable. Build reusable systems for the things you'll genuinely reuse, designed general and decoupled to be actually reusable, and they pay off by saving time on future projects, accumulating a library of reusable systems that speeds your future work, rather than the wasted effort of poorly-targeted or non-genuinely-reusable systems. The reuse justifies the extra design cost, so build reusable systems for genuine cross-project needs, designed to be genuinely reusable.

Trust behaviour over opinions

People are unreliable narrators of their own experience — they're polite, they rationalise, they suggest fixes that miss the real problem. What they do tells the truth that what they say obscures: where they hesitate, where they get stuck, what they ignore, where they quit. The most valuable feedback is usually the behaviour you observe, not the opinion you're offered.

This is why watching beats asking, and why real data about what players actually do beats any amount of speculation. When several people stumble at the same spot, that's a problem worth fixing, regardless of whether any of them mentioned it.

Ship it, then learn from it

No amount of internal deliberation substitutes for the information you get the moment real players touch your game. The assumptions that felt certain turn out wrong, the feature you doubted becomes the favourite, and the problem you never imagined is the one everyone hits. That feedback only exists on the other side of shipping.

So bias toward getting something real in front of real people sooner rather than later. A rough thing that's out in the world teaches you more in a week than another month of private refinement, and every release makes the next decision better informed.

Cut the feature, keep the focus

The instinct to add is far stronger than the instinct to remove, which is exactly why most games drift toward bloat rather than clarity. Every system you add has to be built, balanced, debugged, and maintained, and it competes for the player's attention with everything else. A focused game that does a few things excellently almost always beats a sprawling one that does many things adequately.

When you're tempted by one more feature, ask what it costs and what it competes with, not just what it adds. The discipline to keep a game focused is what lets the parts that matter shine, and it's usually the difference between a memorable game and a forgettable one.

The player doesn't see what you see

You know where to click, which path works, and what every system is supposed to do, because you built it — and that knowledge makes you the worst possible judge of how your game reads to someone encountering it fresh. The confusion you can't feel is exactly the confusion that costs you players.

This is why fresh eyes are so valuable and so uncomfortable: they reveal the gap between the game in your head and the game on the screen. Put your work in front of people who've never seen it, watch where they stumble, and treat that stumble as information rather than as their mistake.

Default to the boring, robust choice

It's tempting to reach for the clever, novel, or technically impressive solution, but in production the boring choice — the well-understood approach, the proven pattern, the simple implementation — is usually the one that ships and keeps working. Cleverness has a way of becoming the bug you're debugging at 2am six months later.

Save your novelty budget for the things that actually make your game distinctive, and be conservative everywhere else. A game built on robust, unremarkable foundations is one you can keep building on, while one built on clever fragility is one that fights you the whole way.

Reusable systems save time on future projects, but only if built for things you'll genuinely reuse and designed general and decoupled to be actually reusable. Build reusable systems for your genuine cross-project needs, designed general and decoupled, so they pay off across projects rather than being wasted effort.