Show % Complete Without Pre-Scans
If I have a backup job scheduled, that has successfully run in the past, use that job's totals for an estimated % done of the next run.
For example, if yesterday I had a 100gb backup job, assume that this job will take 100gb as well, and show the % complete while the job is running.
Maybe display in the format of "50% (est) ". Maybe even check only the previous successful run, to keep it fast.