useMemo

When the calculation is cheap and the value does not need a stable reference
useMemo is usually unnecessary for cheap calculations whose result does not need stable identity. It is most useful when an expensive calculation can be skipped, or when a stable reference helps memoized child components or other Hooks avoid unnecessary work.
When the calculation is slow and dependencies rarely change
When the value is passed to a memoized child component
When the value is used as a dependency of another Hook