I spin 15 or 20 minutes at a time every day. If I have time in the evening, I might do 30 minutes. Looking back, I'd say the beginning failures are the worst. Over time, you work on your coordination, and the yarn looks much better. What we're working on now is consistency and control.
Beginners strive for consistency in how the fiber looks after it has gone through the wheel.
Beginning yarn looks thick, coarse and lumpy. Control pertains to having all parts of the body moving at one time, keeping the treadles at a slow and steady pace. It's more difficult than it appears. Sister William Eyke pumps her feet at the spinning wheel. It really takes some coordination.