The Lifespan Paradox
Mutability × Time: The Compound Risk – Part 1/4
We built a status manager that could manage any agent's status. The problem was, it could manage every agent's status—simultaneously. What seemed like elegant reusability became a debugging nightmare when multiple workflows started stepping on each other's data, each convinced they were the sole owner of the manager's attention.
This isn't just a story about poor API design. It's a manifestation of a deeper truth: in software, longevity is not always a virtue. The longer a mutable instance lives, the more opportunities it has to accumulate damage, confusion, and unintended coupling. Every additional second in memory expands the timeline of possible interactions, and more interactions mean exponentially more ways for things to go sideways.
Programming is fundamentally about anticipation—we write code to handle scenarios we expect might occur. But as our instances' lifespans stretch and their event possibilities multiply, the combinatorial explosion of potential states quickly overwhelms our ability to predict and control behavior. Without time, there would be no state; static data simply is. But the moment we introduce change over time, we compromise predictability.
The paradox reveals itself: we design instances to be long-lived for efficiency and convenience, yet every moment they persist increases the probability they'll betray our assumptions. The immortal mutable singleton and the ephemeral value object represent opposite ends of this spectrum—one accumulating risk with every state change, the other existing briefly and dying clean.
Best Practices Design Philosophy
Jun 14 2025