I've been grouping all my lots together up till now. The Spawners are in a another layer all together. It's getting daunting however, to be able to find things. That's why I'm planning on switching to a neighbourhood layer plan. Then everything in that area will be together and hopefully easier to manage with many more layers. As I understand it, layers have no effect on game play (except the grouping of trees which should be in one layer) I'm also getting used to naming all my lots and giving them addresses (I still need more street names etc. I'm using names from Aldous Huxley's book 'Island' for inspiration. It's been a while since I've read it. I guess I'll have to read it again. I'm also naming all my spawners based on location and type.