I could only dream about your schedule.
I was thinking, wow, at university I had classes from 8am to about 4pm 4 days a week (Wednesday afternoons were "free")
Evenings were spent cracking the books and in the computer lab when I needed access to resources I couldn't get over the network.
Still managed to work part time.
Tasks can expand to fill the allotted time, that's true. But, conversely, if you don't have enough time to contemplate and to fail, you often don't chose the best route. You do what's familiar rather than what's correct.