Frame 5: Optimise for the common path
=====================================

Spec: descriptive guidance, not a checkable rule.
It carries no forbidden and instead pair, and no `jig check` detector applies to it directly.
Section: Principles
Group: Frames

**Ask: what are most people here to do?**

Roughly 80% of effects come from 20% of causes: most users touch a small share of features, most attention lands on a small share of the page, most complaints trace to a few issues. The number is not the point — the asymmetry is.

Effort should follow it. Make the common task excellent before making the rare one possible. A checkout that is flawless for the standard order and merely adequate for the edge case beats one that is uniformly mediocre because every case was treated as equal.

**Use it like this:** when a design is getting complicated to accommodate a case, ask how often that case occurs. If it is rare, handle it somewhere else — a secondary flow, a support path, a manual step — and keep the common path simple. Complexity added for a rare case is paid for by every user on every visit.

**Caution:** this frame prioritises effort, never access. "Most users don't need it" is a valid reason to move a *feature* off the main path. It is never a reason to skip an accessibility requirement — that is Frame 1, and Frame 1 does not yield.