I almost always read multiple books at the same time. The biggest reason is I have an audiobook, ebook, and print book started at all times. This allows me to always have something to read no matter what I'm doing.

I do need to make sure they are not similar in any way, which usually isn't a problem since I read a variety of genres. I read social justice, history, and politics, which can often take an emotional toll, so I like to break it up with something light and cheerful. Sometimes I have what I call a long read, something that I need time to digest in small portions at a time, so I'll read other easier reads while working on the long read.

I think 4 would be my max. If I have too many started, I'll focus on one and finish it so my attention isn't split too much.

I think of it like how we used to watch TV, we often watched several weekly episodes of different shows. Of course these days, you can just binge-watch a whole series, but I think we catch more details when we read or watch over a longer period of time.