I enjoy watching random girl group dance covers by dance groups and I saw about 15 of those yesterday because I haven't seen them in a while.
They were mostly for GOT ~ Step Back and the rest were for GG's Forever 1.
And I've always wondered how long it took them to memorize the choreography because, for a casual viewer like myself, they did it so amazingly and seemed to nail it precisely-- around 90 to 95% of the time.