The pull in both directions
A simple design solves today's problem directly and is easy to understand. A flexible design adds configuration, abstraction, and extension points to handle futures you might face later.
Every bit of flexibility has a cost in complexity, so the two are in tension.
The cost of premature flexibility
- Abstractions built for imagined needs add layers that everyone must read through to follow the real logic.
- Generic, configurable code is harder to test and reason about than code that does one concrete thing.
- Guessing the future wrong means you carry the cost of flexibility without ever using it.
When flexibility earns its keep
- The variation is known and near term, like supporting two payment providers you already have contracts with.
- The cost of changing later is genuinely high, so paying now is justified.
A guiding heuristic
Prefer the simplest design that solves the present problem, and add flexibility when a second concrete case actually arrives. Three real cases reveal the right abstraction far better than one imagined one.
Earn abstraction with real cases rather than guessing.
Key idea
Simplicity solves today clearly while flexibility prepares for futures at a complexity cost, so add abstraction only when a real second case justifies it.