I have been tasked with managing our collection of approximately 50 add-ins/apps. Since we have a community license they are all free.
1. Is there any way to know the last time an add-in was used?
2. If I remove an add-in what happens to any custom fields that were installed with it? Are they kept associated to the pre-existing issues? I don't want to break anything.
Here is an answer that may help you: https://community.atlassian.com/t5/Jira-questions/Is-there-a-way-to-identify-in-JIRA-which-Plugins-are-being-used/qaq-p/372212#:~:text=There%20is%20not%20a%20standard,you're%20hoping%20to%20find.
I currently manage apps for my organization. I have a page where I list the apps installed, who requested them, and what they are used for. However, when assuming this responsibility, I simply did a survey to identify that information and in some cases asked if it was actively being used, and if I didn't receive an answer I uninstalled. If anyone complained I would re-install, but there were no complaints. The note in the answer above about seeking out custom fields to identify when they were last used is a great way to determine if an app is truly in use. In the case of my apps, the custom fields remained after the apps were uninstalled and I went through and hid any custom fields that we no longer used and deleted any that were potential duplicates. I hope this helps you determine which direction will be correct for your group.