I recently purchased a Kindle and I have found that when I have finished a book, I want it in a physical copy. Also, if you look closely at this picture, you will find that books within a series are different shapes and sizes and distinctly not matching when they are supposed to be.
There was once a time where I needed to have book in a series or books by the same author in the same editions. Nothing annoyed me more than seeing books of all different shapes and sizes on my shelves when they are supposed to be the same.
However, I have found as I have got older, that no matter what, the content is still the same and in the end, a book is still a book. As much as I would like to have all of the same editions and all the same books, but I don’t have neither the time to find them or the money to buy them. If I do come across a beautiful edition I may try and seek it out, but nothing more.
The only small rule I have is that if I start a series in a certain format, whether it be ebook or physical, I have to finish the series in the same format.