I store everything in my Calibre library redundantly - both as an AZW3 and as an EPUB. If the original was a MOBI (which is rare), I convert that to my preferred two formats then delete the MOBI. These conversions are done as part of my input process into Calibre, not on-the-fly later. I do not keep track of which file was the original format. But if I really need that info, I could look at the file timestamps in Calibre's directory structure to determine which file came first.
Is this a waste of disk space? I currently have 8900 novels stored in both AZW3 and EPUB format. This takes 8Gb of disk space for the redundant storage. That is not an amount that I am going to worry about.
|