We all know the drill. You have a feature class in SDE you can't change schema to because a service somewhere is using it. But what service? You probably have hundreds if you're in government. Not a great use of time. And a tracking spreadsheet is not a perfect solution for various reasons. There should be a button to show what services on what machines are using a feature class. With an option to stop one or all of them right from that dialog.
Going the other direction, there should also be a way to see what feature class is being used by a service. This is key with Locators because unlike a regular service they don't tell you where they are pulling data from, period. You have to write that down upon creating it, or you can't determine the data location, from what I can tell. I propose that in the published Locator, in Service Properties it should state the actual locator's file path it's pulling from.