~なくていい (don't need to)

The permission/no-obligation pattern [verb-negative stem]+くていい, 'don't need to X / don't have to X / it's fine not to X' — literally 'even without X, it's good'. The focus particle も may be inserted (~なくてもいい) for a slightly more explicit 'even if not' flavor; both forms are interchangeable in everyday use. Standard way to deny obligation; counterpart to ~なければならない ('must').