Cellular PVC decking (TimberTech AZEK, Fiberon Paramount) has the longest service life in Utah’s conditions — 30–50 years with minimal maintenance — because it contains no wood fiber, absorbs no moisture, and resists UV degradation better than any other decking product. Capped composite decking (Trex Transcend, TimberTech Legacy, Fiberon Wildwood) is a close second at 25–30+ year service life and the best overall value for most Utah homeowners when 20-year total cost including maintenance is compared. Natural wood requires more frequent maintenance in Utah’s high-UV environment than in most U.S. markets: pressure-treated wood needs annual sealing (not biennial as often recommended) and has a typical Utah service life of 15–25 years with consistent upkeep. The material that lasts longest in Utah is also the material that comes with the most meaningful warranty — and cellular PVC products from major manufacturers carry 50-year warranties with transferable-to-buyer provisions that matter at the time of home sale.