A multiple-of-8 (or 4) scale gives consistent rhythm and predictable layouts.
Pick {4, 8, 12, 16, 24, 32, 48} and use them everywhere — no arbitrary values.
Choose a fixed set of spacing steps, say 4, 8, 12, 16, 24, 32, 48, and use only those, and a layout snaps into rhythm: gaps repeat, cards line up, and nothing lands on a stray 13px by accident. Most systems, including Material and the token sets behind shared Figma libraries, build on a 4 or 8 base for exactly this reason. Eight also divides cleanly across common screen densities, so edges stay crisp.
Hairline borders, focus rings, and optical alignment often need sub-scale values like 1px or 2px that no 8-point step covers, and that is fine: the scale governs layout spacing, not every measurement. Dense professional tools may also adopt a tighter 4-point base so more information fits without feeling cramped.
A teammate's profile card uses gaps of 6, 11, and 13px — no scale, just values nudged by eye. It looks subtly broken and no one on the team can say exactly why.