My work has varied in time to completion. My first piece ever took exactly one year to the day, but only because that was the intention. On average, they take about 2 to 3 years to complete, each.
Generally, there is a decent amount of sound involved. Often times either a podcast or music is being listened to, actively, while the hand works. When I am lucky there may be a cold brew of some sort, at the ready.
This is of great interest to SirScribbley as well... Time will tell.