Seeing progress is motivating
There's always this question of what to do with the Kanban cards once you've finished with them – once features have made it all the way across the board and been deployed into production. What do you do with the cards? Do you throw them away? Do you keep them as souvenirs? Do you pile them up? What do you do with them?
I recommend keeping them. Not just keeping them, but putting them on display. It's a real motivator – a visual reminder of the progress you've made. And it's not just you it helps, it also reassures the sponsors and helps them appreciate what you've done. Even though they can see the software as it evolves, it's easy to forget all the work that's gone into it. Seeing the cards reinforces the point. This is my experience anyway. So, my recommendation is keep the cards as long as possible and keep them as visible as possible.
Obviously you don't want to clutter up the board, so maybe you want to move them onto the wall or somewhere nearby but make sure you don't throw them away. They're important.