I found that around an hour is usually enough time to complete an origami dinosaur. The great thing about this is if you get stuck or frustrated you can step away from the project to run some errands. When you come back, the step will most likely appear easier, as your mind has had time to subconsciously figure out the fold while away from the project. When you complete the dinosaur you will have a great sense of accomplishment knowing that you created a paper dinosaur without the use of scissors, glue, or tape but only using your hands and a square piece of paper.