Building codes give reasonable assurance a home is safe from structural failure, fire hazards from electrical and heating systems, electrical shock, and health risks. The permits provide a permanent record of the work performed and inspections conducted on the project. A building inspector ensures the work is done safely and to code when you obtain a permit.
Some homeowners find when trying to sell or refinance their homes, prospective buyers or lending institutions want proof that alterations are in compliance with local codes. There is no proof without a permit and inspection on record. The homeowner must then apply for a permit with no guarantee the remodel will meet the codes, and face the possibility the remodel must be redone or removed. This could delay refinancing or cost a sale of the home.