I only use 1x speed for audiobooks, i listen to them whilst at work and I want them to take up as much times as possible for me. I also don't want to miss anything if I'm concentrating a bit harder on a specific task I'm doing. Where as something like youtube I watched everything there on 1.75x speed because that is my own time and I want to get the info as quickly as possible.

I never read however. I've enjoyed getting into audiobooks because of the fact I find reading absolutely mindnumbing and it sends me to sleep so I'm glad to be able to experience all the good stories out there without having to read xD