[MENTION=790755]serpens[/MENTION] - I suspect that depends on the exact cruise line. I checked the big 3 mass market and FCC language states they expire within the next two years or so. I don't see any which allow it to be transferred to a third party, either (selling it) but haven't looked too closely.

Carnival: https://unitedcruises.cruisehelp.com...3-July-31-2020
RCL: https://www.royalcaribbean.com/faq/q...20is%20further).
NCL: https://www.ncl.com/why-cruise-norwe...usiness%20days.

In pre-COVID times, many of the mass market Caribbean sailings were kind of "close enough" to pick one with the best deal, especially if booking after final payment for non-peak sailing, departing within a few weeks of each other. They just about all left Friday-Sunday anyhow. Cash allows that possibility and can re-cancel without losing credit validity, plus gain any perks for new booking. I've cruised both ways - booking years in advance for rare routes and that same month for more common routes.