G'day Rick,
It can be used as long as the supply lasts, 1-2-5-10 seasons+. No rules to the contrary.
Fake Left is one example. Classic Garry also had some frozen semen stored as I recall but from memort it wasn't as successful as Fake Left was in terms of getting mares in foal. No doubt there are others. Bettor's Delight for example has a sizeable quantity of frozen straws in storage both here in Oz and in NZ.