Each time you reach a new tile milestone in the new year, you’ll have the chance to either:

• keep the current perk (which extends it through the end of the following year) 
• swap it for a different perk (which will be valid through the end of the following year).

If you choose to replace the current perk, it will expire the day you select the new one. 

Please note that Perks You Pick must be extended or replaced in order of their initial selection.

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It is a part of the program. If for instance you selected 20 tile points, you can select 20 tile points again to use through 2024. I selected the 20 tiles one twice which generated 40 extra tiles which then put the total over 100 tiles which opened up another perk to choose 15,000 bonus points. It is a bit unclear though if you don't select the same one twice, I would assume the 20 tile points stay and the new one is selected--though the wording seems to indicate the first one is taken away.