A lot of people don’t think copy editing is that important, or that it’s only important for professional publications. Not surprisingly, as a copy editor, I disagree. For instance, check out this sign at a local tailor’s shop on the way to my gym:

See if you can find all the grammar and spelling errors (there are three, though one’s pretty hard to see in this photo; sorry - took the photo from my car as I waited at a stop light).

Someone must have pointed them out to the shop, because the sign was up one day and down maybe two or three days later. Still, it doesn’t reflect well on the tailor or the sign shop that no one knew enough grammar or spelling to catch these mistakes - they would have taken but a minute to fix.