This product comes with a factory oil finish and is delivered ready to install. Oil finishes are applied to achieve the desired color, offer better color longevity over time, and to bond in surface soot. Refinishing every 2~15 years will slow down the aging process and allow the siding to retain the specified color longer. However, this is a maintenance-optional product due to heat treatment. Touchup oil for end cuts, notches, and rips is included with each wood order shipment.