Same as guitar heaven, when I get back to garageband my old project greeted me. I had some other stuff in mind but not particularly. So I did give it a go after a week also. And manage to add couple more layers of riff and was satisfied with it. (Good enough)
When I do go back to the same peiece it seems to add up, tho it is a challange not to over due. In this particular song bit I think I did cross over a little bit but than figure out it was getting way too unnecessarily busy, managed to stop.