The actual mix took less than one hour, not counting the mix preparations (routing, peak balancing, ...). I've made a habit of mixing very fast and not get lost in details. After 1 - 2 hours I'm usually done with a mix and move on to the next song. A couple of days or weeks later I listen to that rough mix again and do some fine-tuning.
In the past I spent much more time on each mix, until I realized that I always ended up losing my focus that way.