I am an Encore Bride, and an Older Bee (over 50)
So maybe I can shed some light on this tradition
This is an old fashioned tradition, based on a different time (and cake)
It really doesn’t translate well to modern times, and your basic White Cake with Buttercream Icing
My First Wedding (circa 1980) we had a traditional Wedding Cake for the time which was Fruit Cake… heavily laced with Rum (or other heavy liquor like Cognac)… then covered in Royal Icing.
After the Wedding the tradition was to save the top layer for the Christening of the first Baby or a Milestone Anniversary.
One would wrap the cake tightly in Saran (or Wax Paper), then in Tin Foil, and then put it into a cake box or Tupperware Container before slipping it all into the Freezer
(Altho I do know some people who just stored it in their Fridge equally as well. In so much as the Cake is full of alcohol… if stored in the fridge, one would cut-off the Royal Icing… as it tended to pick up some flavours off the air in the fridge over time… and voila perfectly preserved Fruit Cake… 5, 10 or more years later)
My First Hubby & I stored both the top layer from our Wedding Cake along with quite a few individually cut & wrapped pieces. And everything kept quite well. We served the top layer at the Christening of Baby # 1. And we still had some “spare’ individual pieces floating around 10+ years after we married… and all was well.
To be honest, I’ve never heard anyone have much success with regular Cake & Buttercream Icing even a year out from the Wedding. White Cake, Pound Cake etc, with Buttercream or Fondant Icing which is now what most WCakes is made from is just too fragile to list any sort of time in a Fridge or Freezer.
There are lots of disappointmenting stories here on WBee to that effect.
IF that is what you opted for, you might want to look at having a Baker make you a “similar cake” to the Original to mark the future milestone.
Hope this helps,
PS… I didn’t vote because I’d have 2 completely opposite situations… one that worked really well… and one I was smart enough to realize doing so wasn’t realistic