I posted earlier on the costs of Autorefresh when over-using it in the Classic interface. Which then brings us to the question: how do you determine if someone is using Autorefresh, and what are they likely using as a refresh interval?
There is one very handy classic command that can tell you a lot about what is going on. The .VTM command will show information on sessions connected to the Classic task. Most important, it will show the last time the session was updated, either by the user hitting enter, or the screen being refreshed via Autorefresh.
Here is an example of the .VTM command in use. In the example you see three sessions. The middle session is my own session, and I can infer this because the Last Update time stamp matches the time on the top line of the screen. The bottom line is probably a session between OMEGAVIEW and OMEGAMON. The top line is the one of interest. If I refresh my screen a few times, I will see that the Last Update column for the session in question increments on a fairly regular basis. By watching that number you can infer that the top line is a session in Autorefresh mode, and what the interval is (in this example it is at the Classic default of 5 seconds).
Once you know that Autorefresh is being used, the next step is to locate the user in question, and ask them to either set the interval to a higher number, or to discontinue using Autorefresh mode.