Similarly to what Jira is doing on their Kanban boards, I would LOVE to be able to quickly see how long a task has been stuck in a certain column. You can see how Jira handles that here – https://support.atlassian.com/jira-software-cloud/docs/customize-cards/ – but any visual indicator would do.
USE CASE: Sometimes we have a lot of tasks on boards, especially in larger teams and when we're dealing with plenty of ad hoc requests. A way to determine the task age at a glance would help us see if there's anything on the board that's been stuck for more than necessary.