This question could be read two ways:
- Have I ever read an entire series of novels from start to finish i.e. read all the novels in a series? or
- Have I ever read an entire series of novels from start to finish i.e. back to back without reading anything else in between?
I’ve read a lot of trilogies and longer series as they have released.
The longest single series I can remember reading is Karen Kingsbury’s Baxter series, which might not count because it was actually divided multiple series. I stopped reading around halfway through the second four-book series because the story was straying away from the original characters.
Back when I used to buy lots of paperbacks, I would often reread a series from the start every time a new book was released, partly to remind me of where the story was up to, but mostly because I enjoyed reading but was on a budget so couldn’t buy endless paperbacks (there was also the small problem of storage). I don’t have the cost or storage problems so much now I read ebooks, so reread less.