I have been an aspiring writer of sorts, and wrote articles at least once a week for several years without getting much if any feedback on the quality of my writing as opposed to its content. It is fairly easy for me to look back and see a steady improvement in writing quality. I also usually (not always) have no trouble knowing which of my writing isn't any good, and don't remember it having been otherwise.

I could be deluding myself but I certainly think some of my writing is better and some of it is worse.