I also advocate replacing the entire series with e-books. I have done so with at least 4 series, and I only start new series as e-books. There are several major benefits for me:
Space! My precious bookshelves are being overtaken by board and picture books
Heft - at least 3 series I like to re-read have books that are 800+ pages.
Wear and tear - some of the long-running series are in rough shape because glue has let go, or the paper has yellowed to the point of illegibility. Some mass market paperbacks don't hold up to much abuse.
Dust - hubby and son are both allergic and books are dust collectors.
For series reading, whether hefty titles or not, it is SO easy to do a find on the device and look up a detail in a previous volume. I love being able to look up an obscure character or place rather than having to re-read an entire series EVERY time a new books comes out.