Recently Giuseppe Castellano, art director at Penguin Random House, tweeted that the #1 issue he has with illustrators is lateness.
Today I was on the phone with a different art director, and he said the exact same thing.
We love to moan about how no one respects artists these days, how it's so hard to make a living as a creative, how everyone wants artwork for free, the market is so oversaturated with talent, blah blah blah. And then to turn in late work to big-time paying clients? Illustrators: what are you thinking???