Why bother
The failure is always neglect.
Cards do not degrade in any interesting way. What degrades is the match between what you stored and what is true, an account closed, a phrase replaced, a code changed after a move.
The other slow failure is memory. A password you have not typed since last spring is a password you might only mostly know.
So pick a date you will not forget, a birthday, the start of the year, the day the clocks change, and spend an hour.
The routine
Four steps, once a year.
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I
Account for all three
Physically find each card. A missing copy you discover in an emergency is much worse than one you find in March.
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II
Read one
Open a card on your phone and enter the password from memory. This tests the card, the app and you.
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III
Update the vault
Remove what is dead, add what is new, correct what moved. Keep the list short.
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IV
Rewrite all three
Every copy gets the new vault, then goes back to its place. Note the date somewhere harmless.
An hour a year
is the whole upkeep.