There is a shelf life to beard and mustache care products with some clear signs of when that actually happens. As I've written and talked about before it is important to keep your beard and mustache care products store in a cool, dry, dark, place. This will help keeping your products fresh. Using your products within 1 year of purchase is ideal.
Some clear indicators of a product going bad are a rancid smell or no scent at all. The product itself might not be detrimental to use as far as effectiveness but the last thing you want to wear on your face is something that smells terrible from going bad.
When it comes to control products such as beard balm, beard butter, and mustache wax, the products can become brittle and crack. You can always try and add some beard oil to it and see if it revives it a bit. Otherwise, it will be incredibly difficult to apply it effectively. Check out the video below as I discuss shelf life and how beard products can go bad.