I find there's always one "problem" when you build a model from scratch: When you first start it, it goes real fast. After a couple of days you already have something that looks like an unfinished Millennium Falcon. It's very rough, but since you've been working with big parts, you have an impressive model. Then, as you work along, the parts get smaller and smaller. You put more and more hours into the model but you don't really see as much progress. And weeks later, you still have an unfinished Millennium Falcon model. And months later: an unfinished Millennium Falcon model!