I work with Web Maps which can contain a large amount of layers in them for various different teams. It would be incredibly useful to have a mechanism either within the map or feature service which indicates the last time the service was accessed (e.g. when it was last switch on in a web map). We can then look to remove layers that aren't used often and potentially remove the service to reduce storage requirements.
This might be a difficult thing to achieve but if you don't ask you don't get I suppose!
