Hi, Kathel!
Congratulations to the bride and groom! Walt Disney World is a wonderful place for a romantic honeymoon.
Adding on the No Expiration option is up to you, it is something you will have to do the math on. Adding on this option is currently about $270 plus tax per ticket (prices subject to change). This is equal to *about* a 3 day ticket. If you have 3 or more days left, then it might be worth the investment.
OK, here is where it gets complicated. If you are a fan of using the water parks, it might be worth the upgrade to hold on to the Water Park options for years to come. This does add value to that upgrade.
If you decide to upgrade, it must be done before you use up your last day of tickets and within 14 days of the tickets first use. The upgrade can be made at any guest services window.
And a final thought: only do the upgrade if you know you will not lose your tickets! Put them someplace safe and make copies or take pictures of your tickets so you have as much information about them as possible in the event you forget where you put them.
I know there is a lot of information about the tickets, so
let me know if you need clarification on how this all works! Good luck to you and wishing the happy couple a very "Happily Ever After!"