One of my favorite underrated (and underused!) CSS properties is
Tabular numbers are monospaced, which keeps their sizes consistent and keeps numbers with the same amount of digits aligned.
There are two common cases that warrant tabular numbers: tabular data and moving numbers.
I suppose it's in the name. Numbers (especially large numbers) are easier to scan when they're tabular.
When numbers are updated in place (like a timer), tabular numbers keep them in place.
font-variant-numeric: tabular-nums is available as
.tabular-nums in Tailwind.