One of the opportunities redeveloping a previously-used creative is a pleasing chance to check in with how I've progressed at the ol' illustration. To be fair, I could do the same thing with a creative I produced three months ago and it would look better - stuff does tend to look better when you have a chance to put stuff away and come back to it. But the nature of the job is that it goes out when its fresh and raw.
I think of it like a pancake batter. Sure, it's best after it's had 24 hours in the fridge. But you want pancakes when you want pancakes, and they're still delicious with freshly-made batter.