1,799. When to Write a Get in the Future
Hilchos Geirushin 9:23
If a man tells others to write a get for his wife and to deliver it after the current Sabbatical cycle, they must write it within the first year of the next cycle. If he told them to write it after a year, they must write it in the first month of the subsequent year. If he said after a month, they must write it in the first week of the next month. If he said after Shabbos, they must write it before Tuesday ends. If he said to write it before Shabbos, they must write it sometime between Wednesday and Friday.
Hilchos Geirushin 9:24
Let’s say that the agents procrastinated and didn’t write and deliver the get at the designated time, such as if he told them to write it after a month but they wrote the get and delivered it after two weeks into the next month. In such a case, the get is invalid.