Do collections expire?

In every ending there is a new beginning - Seneca

The Uptrip cards don't expire, they are truly yours forever. However, collections expire. This may happen when the all rewards have been redeemed or on a specific date.

When a collection expires while you were still collecting towards it, all your cards will be released and will be available to be re-assigned to other collections. Don't worry, you won't lose them!