I've been teaching college courses for more than 15 years. Sometimes I like prepping for class, other times I let it go and procrastinate. Early in the semester I find myself abiding by good habits. I prep well ahead of time. I'm not rushing my prep, nor am I spending a ton of time on prep. There have been times where I spent a long time preparing content for a class session but the class ended up poorly. How? I think I run into trouble when I spend too much time on content and not enough time thinking about actually teaching the material. If time permits and I have a session prepped long before I actually teach it, then the material is in my head and I can think a lot about how I want to present it. I think about new discussion questions and, frankly speaking, a few new jokes pop into my head that I may or may not end up using.
Time is a precious resource, of course, and not everybody has the same amount of time to dedicate to class preparation. Advisement, research, writing, meetings, OTHER JOBS, children, housework, social lives all take up time. But if time is on your side and you can manage to complete your class prep early, I think it may work in your favor.
On a related note, I think when my class prep is sloppy I tend to go too fast in class. My pacing is off. I talk too fast, don't give students enough time to respond to questions, I don't settle into the class, etc. It's like I'm fighting the clock. But if I finish my prep comfortably ahead of class time then I find my pacing is much better. When I'm settled in the clock is my friend. It seems to move at the right speed, giving me plenty of time to cover the material in a way that doesn't feel hurried.
It's easy for me to say this in September before it's hit the fan. Like I've written before, it's dancing in September and struggling in December. My goal is to stick with the best habits I can for as long as possible this semester.