How often should I review connected apps?

I have connected several tools to my account and forgotten about some of them.

Review access when you stop using a tool or after an important account change. Revoking authorization is different from removing an app from a device.

Does revoking a connection also remove information the other service has already received, or is that a separate question?

The difference between uninstalling and revoking access is useful. I'd want both steps included in a review checklist.