well, normally, what`s being learned is, when to go and get a coffee/smoke a fag, while the dirge is being minced.
I mean, sure you can look at it as learning.
But I know plenty of people, who hammer away, who have been sending me stuff for critique for ages. I`ll name no names, but the same problems come up again and again, so nothing is being learned.
I`m not saying just leave your studio until you are bursting with maximum inspiration, but I am saying, you have to know when to walk away.