Ask what decision each number drives
For every metric on the dashboard, name the last decision it changed. If you cannot, it is a candidate to drop.
Drop raw counts without context
Total tickets closed says little. Per-agent counts can even encourage rushing, so look at outcomes such as repeat contacts.
Be wary of metrics that can be gamed
Closing tickets quickly, or counting auto-replies as first responses, makes the number look better and the service worse.
Keep a few that guide action
Most small teams need first response time, resolution time, satisfaction and backlog age. Add others only with a reason.
Review the list each quarter
Needs change. Once a quarter, remove one metric and add one only if a real question needs it.