# Rule 4: Axis readability

## Intent

Make scales, units, and category labels easy to read and easy to interpret.

## Pass signals

- Tick labels are legible
- Units are clear
- Axis titles exist when needed for interpretation
- Label density fits the available space

## Fail signals

- Tiny or overlapping tick labels
- Ambiguous units
- Missing axis titles where the measure is unclear
- Extreme text rotation used as a workaround for poor layout

## Reviewer guidance

Prefer simple fixes first: improve spacing, shorten labels, or flip orientation before accepting unreadable ticks as unavoidable.
