Originally Posted by ccowie
I do keep all my Epubs for that reason.
Regarding performance there is something I find a little peculiar. My books to tend to perform better when I'm reading them. The page turns a little quicker and I can navigate back and forth from a table of contents better. But, after loading new books LRFs take a lot longer to format and a lot longer to adjust to a new size. Epubs take no time at all.
I think I know the reason for that. LRF are in binary format. In other words, with a new book, your reading device has to parse the "code" first and turn it into the intended text outcome. It may then cache the outcome to make subsequent loading and page turning faster.