0 used to describe something that is only available once or that will only happen once: --
Take advantage of this one-time-only special offer!
Assessments are generally one-time-only payments made by the union member to the union to cover a special program or activity.
They are often held annually, but are sometimes held as one-time-only events, to celebrate the occasion.
NYA ORD
European
May 10, 2021
DAGENS ORD
Shimmer
one-time-only