Last Xmas I gave one brother a $20 Google Play Store gift card because he has an Android phone. These cards are good for 12 months & he has never redeemed the value of the card, just left it in a drawer at Mum's place. I recall it was a couple of days before Xmas last year that I bought the card, so I felt there was a chance it would come in under twelve months if redeemed today.
It did, & now I have $20 in my Google Play Store account. I'll use it for books & movies & reimburse $20 to my brother.