The moment your if/else wants to become a Strategy

Tap to add a case. Watch what happens to the cost of the next change. The pattern only earns its place at a certain point — this shows you where.

Your code 3 branches

Cost of the next change low

Two or three fixed cases. A conditional is the honest answer here.

keep it simple pattern starts paying

Same behaviour, different shape

Why Strategy fits here

Each branch is a whole way of pricing, not a value.
The branch is chosen by a type that keeps growing.
New types arrive without touching the code that uses them.

When it does NOT fit

If the cases are few and frozen, the if/else is cheaper. Adding a Strategy interface for two values that never change is over-abstraction — the abstraction outlives its reason.

Pattern Fit · a teaching sample