Louvers - or gable end vents- are a must for attic ventilation.  They prevent moisture build up in the winter and create air flow in the summer to reduce the heat build up, both of which are necessary to keep your home from having mildew, rotting and other issues you won't want to deal with.  The life of your roof will also be extended if you have good airflow in the attic.  Most people will do the simple thing and order a stock size in White, but...ANY size, shape or color is available from New Concept Louvers, Inc.  They are both aesthetically appealing, functional and maintenance free.  For more information and pricing you can contact us at 800-635-6448.