The credit Alaskan gave me for temporarily losing my luggage was only good for a year. I'm flying WestJet this year so won't get to use it.
Most Airlines I’m familiar with are one year. I do think you can combine and transfer them though. I’m pretty sure my buddy took his family on a trip they took the deal, the. His wife and him used all the vouchers to go to Hawaii and got the flights for free.
All I have in this world is my balls and my word and I don't break em for no one.