No paint job will last forever. However, the life of paint can be extended with the proper care and maintenance. Interior paint is generally not subjected to conditions as harsh as exterior paint. Maintenance usually consists of little more than occasionally cleaning to remove dirt, grease, or fingerprints. Scuff marks, scratches, and chips require touch up.
Exterior paint requires considerably more maintenance. Regularly removing dirt and mildew will not only keep the paint looking fresh, but will also prevent mildew growth from destroying the paint film. In addition, an inspection for rotted wood and cracked caulk should be conducted at least once a year.
Promptly replacing rotted boards and repairing cracked caulk will prevent more extensive and expensive damage.