The amount of line needed depends on where you plan to hunt. The deeper the water, the more line you need. If the weight does not touch the bottom, the weight on the bottom will cause your decoy to be pulled partially underwater, which takes away from lifelike qualities and be more likely to drift away. When i tie my decoy strings i have 4 dozen that have short lines roughly 2 1/2 to 3 feet long and also some that range from 10 to 12 feet (conditions that you would not want to wade into, but use a dog or boat).