Hi Dave, Each time I do an update, I save the file with a date, for example, DCC Main Wiring 2020-01-27.xlsx. So that takes care of having previous version available. I am a geek on this type of documentation. In addition to the backups on various computers here in Amarillo, the files are backed up in the cloud. I think we are rock solid. We also do this with things like our rolling stock and locomotive rosters, photos, and correspondence.
