Wood has the advantage of being all natural, the frame uses a foundation comb that bees take to readily. Life expectancy varies depending on how humid and hot your hive is and whether the frames are for brood or honey. Plastic lasts forever if you treat them right, easier to clean but you need to brush on melted beeswax as a "starter" before the bees accept it. I use plastic, but prefer wood. Its purely a personal choice. One of my friends uses wood for brood frames but plastic for honey - swears it makes a difference (for her).