I did the driver's side first, as a test to see how it would work, and if I would like the overall finished look. That took a solid afternoon.
The rest probably took two more afternoons. Plus some general messing around, figuring out how to do the project. I also built a "paper towel holder" to support the vinyl roll to make it easier to do the banner-style cutting.
Lastly, my hand isn't 100% yet, I just got the cast off 2 weeks ago. I think I was still wearing it when I did the driver's side of the car. Only having one and a half hands makes things a little challenging.
Overall, I would say that if somebody else were to do something similar, it's a weekend project.