Other products I have seen track the history of disk space usage and display it with a graph. This is very helpful in seeing usage trends. Please add this feature to Lansweeper. This should be easy, since Lansweeper already gets the disk space information. All it needs to do is save the data over time display it in the asset page somewhere.
On the wish list, but no release date unfortunately. Though this is not exactly what you're after, setting up email alerts for disk space reports might be a workaround for now. This will at least allow you to manually review any changes.