As an adult professional musician (church organist), I discovered that, once I became a mother (a year ago), I had less time to practice (from approx 4 hrs a day to about 1.5 hrs a day), but--now I am learning music far thoroughly because I (and I don't connect this to motherhood) now work in very small batches on each piece (a page a week from 4 to 5 different works) vs trying to tackle much larger chunks of each piece each week. Result is that I learn far more thoroughly than before. Neither in college or grad school (of a prestigious music school) was this level of thoroughness broached. The mentality was to cram as much as possible as soon as possible. And I did, and feel like it gave me less than the pace of work I do now.
This made me wonder, what was the breadth of repertoire expected of professional musicians in various time periods and how was learning of repertoire approached?