Calculating work item age is an essential part of running and optimising a workflow using Kanban practices. So why does a tool as popular as Jira don’t do it out of the box? Beats me but I have figured out how to do it even if you can’t install Jira plug ins - read in here - https://www.balkanski.net/blog/how-to-calculate-work-item-age-in-jira-without-add-ons