Similar to the other options in the current CU interface, it would be good to have an option to list all User Agents for a User or IP that was used in the past 90 days. This will save some time and help the checkusers to perform better.
At times, we end up checking thru many shared IPs a user had used to find a different UA that can connect the two ids in question. It is possible that at a weak moment, we may fail to see the connection as we did not see both sharing that unique UA.