Let's start by saying I'm not suggesting you read a full book per day. What I'm suggesting is to read at least a few pages of a book per day, reading a variety of books over the course of a week.
For a while I used to start book and finish them before starting another one. I'd allow myself to read a fiction book and a technical book at the same time, but not more than that. The idea was that by reading more than one of each my brain would have trouble with context and information retention.
I've recently decided to switch this approach. The main reason was that I found myself spending too much time reading articles online that I thought didn't bring me much value over time. I always thought books were more valuable, but their biggest problem was that it required a good amount of time involvement for the value to kick in.
Just like there are two strategies in learning systems, exploration and exploitation, I decided that leaning more on the exploration side might provide useful. Instead of spending hours on the same book over a short period of time (1-3 months), I would instead read bits of many books at once.
Here are the benefits I've observed through this approach:
It's easier to identify similar sources. I would read a few books on a similar topic, and of course they would all cite the same sources. The difference between processing all those books in parallel instead of sequentially is that you notice the pattern of reuse more clearly. When reading the books sequentially, what happens is that this type of information decays over time. We start to forget what the last book was referring to, so that the next book appears to have new references.
Similar ideas can be identified and speed up reading. As you identify the same ideas in different books, instead of reading the arguments careful in each book, the best argument is read thoroughly and the others quickly scanned for additional information.
You are exposed to more variety. Some people get topic fatigue, which is that you get bored of reading on the same topic. Reading on different topics avoids this issue while also stimulating you to think about many topics. This is a great way to sometimes make connections between unrelated topics.
Overall I've been very satisfied with this experiment and I've been doing it for over 4 months now. I highly recommend it if you have a large list of books you haven't started yet. See my article How to prioritize which book to read to help you organize your reading.