The term evergreen is from the 1640s in reference to trees and shrubs, from ever + green (adj.). From 1660s as an adjective; figurative sense from 1871. A good product should be in a evergreen market. An evergreen market is self-renewing and is stable for decades. An evergreen market has longevity and is continually relevant in a fast changing business universe. Look for products not susceptible to changing culture, a temperamental economy, or fleeting interest.
Always evergreen, momentum in marketing, changing without a changling