Well thats up to you and what you want your project to look like. We are the best at making polka dot wall stickers but we my not be the best at interior design. Over the years we have seen projects using half inch up to 22' and patterns that would blow you mind.The best thing to do is to lay out your design before hand using painters tape to mark guide lines or where your decals will be placed. Then count exactly how many will be needed and be sure to add a few extra for unforseen booboos.