I have a Kindle PW2, a Kobo Aura HD, a Sony PRS-650, and a Sony PRS-350--all still in use. I bring all my books into Calibre and convert them all to ePub and AZW3 so I can read them on whichever device I choose. Maybe a little over the top--okay for sure a little over the top--but to answer your question, I don't find having two different e-readers at all too extravagant. I find it totally sensible.