Not all home improvement projects require a permit, but many do. Whenever there is mechanical, electrical, plumbing or structural work being done, a permit is great protection for the owner.
Getting a permit allows you to have a third-party inspect your property and keep contractors honest in their pricing and quality of work. Some less-than-reputable contractors offer “time delay” as an excuse not to get permits and inspections, but this is usually far from the truth.
Inspections give the owner an independent person to look at the work being done and enforce codes for the local jurisdictions. This is for your safety. Projects that do not meet code standards can be a danger to you and your family and can cause delays in project completion. Getting an already completed project up to code also can cost far more in the long run. Most code enforcement follows the International Building Code (IBC), but local codes vary in every city and town. Having a permit qualifies homeowners for inspections from professionals familiar with national, state, and local building requirements.
In short, having a permit can ensure you are not in violation of local laws and can protect you from contractors trying to cut corners.