Don't Modify Letter Spacing

From the Typography constraints in ibelick's baseline-ui skill. Type designers craft spacing per weight and optical size; overriding it usually costs readability and reads as amateurish. If the text needs more presence, reach for weight or size before tracking. Counter-view worth reading alongside this: content-tracking-is-size-specific argues from Emil Kowalski's apple-design skill that tracking IS size-dependent at the extremes — display type wants it slightly tighter, caption type slightly looser.

The two are not really in conflict: this rule is the correct default for body text, that one is the correction for very large and very small sizes, ideally applied through a variable font's optical-sizing axis rather than a hardcoded value.