Whether you need a permit to build or install a fence depends on several factors, including your location, the fence's height, its placement in your yard, and the materials used. In many cities and highly populated areas, a permit is required, especially for fences taller than 6 feet. Conversely, rural areas may have fewer restrictions. Typically, backyard privacy fences 6 feet or shorter do not require a permit, while front yard fences often have a lower height limit, sometimes as low as 3.5 feet. There can also be exceptions for properties in mixed residential-commercial zones. It's best to check with your local building inspection or zoning department to understand the specific requirements, height restrictions, and location rules for your area. A professional fence installer can help you navigate this process and often secure the necessary permits for you, though this may extend the project timeline.

You can only change your neighbor's fence with their permission. A neighbor's fence is their property, and altering it without their consent could constitute trespassing or property damage, which may have legal consequences. If you have concerns or disagreements about your neighbor's fence, communicate with them openly and try to reach a mutually agreeable solution. If you believe the fence violates local zoning laws or property regulations, consult with local authorities or seek legal advice to address the issue through proper channels. 

Deer can crawl under a fence if it has a gap of around 6 inches or more. Make sure to close all gaps at the bottom of your fence to keep deer out, and the bottom of the material should be tightly secured, or the deer will push right through it. As an added benefit, closing shorter gaps at the bottom of a fence can also keep rabbits out of your yard.

Pickets should sit at least 2 inches off the ground to encourage groundwater to flow underneath. Pickets can sit as much as 6 inches off the ground, but setting it any higher could let pets in or out of your yard unintentionally. These are not to be confused with the fence posts anchored underground with soil or concrete footing.