Tokens are the reusable values in your design system, and each one needs a name. For sizes, there are two common approaches. T-shirt names, like sm, md and lg, are easy to remember and read almost like plain English. Numbered names, like space-4 and space-8, often match the actual value in pixels (sometimes converted from rem units).
Each approach has a trade-off. T-shirt names are harder to extend. If you need a size between md and lg, there’s no obvious name for it so you’ll have to update the sizing system to accommodate that. Numbers extend easily, since you can add space-12 between space-8 and space-16, but they say less about how a value is meant to be used. Either can work well, but understanding their tradeoffs is important before you decide to commit to one.
