All foam latex breaks down over time but in my experience I've found making them last longer depends on how you store them. I have foam latex masks that I've kept on display for the last 18 years and they've started to break down and crumble because of the continual exposure to air, temperature changes and general sunlight. But I also have pieces that are just as old that are still in excellent condition because I've preserved them in Ziplock bags and kept them hidden away in drawers.