I'm more into manga than novels, but it's a love-hate relationship. The downside of manga is that it takes ages to produce, and many mangaka leave their work unfinished for all sorts of reasons - deteriorating health, lack of motivation, writer's block, conflicts with publishers, death... and that's not even mentioning the long hiatuses.
I envy novel readers because novel volumes are usually released more quickly, and most books provide some sort of conclusion. You can start reading a manga in elementary school, continue through middle school and high school, graduate from college or university, get a job, get married, have a kid... and the manga still isn't even close to ending—if it's lucky enough not to have been abandoned halfway through.
Because of that, I don't start unfinished series anymore.
P.S. Greetings to CLAMP. I'm still waiting for you to finish
X, even after this 23-year-long hiatus.