The main benefits of bath bombs are additional hydration and softening of the skin. Depending on which ingredients are included, they could also have additional benefits for treating specific skin concerns. For instance, some bombs may include moisturizing agents for extra-dry skin or natural anti-inflammatory ingredients for eczema.   How often should you use a bath bomb? Most bath bombs can be used at least a few times a week, and if you're a daily bath-taker, you might be able to use one every time you soak. However, if you experience irritation, unusually dry skin, or another skin concern, you may want to use them less frequently or discontinue use altogether.   Do bath bombs expire? Like most other skincare products, bath bombs will eventually expire. While the lifespan depends on the ingredients, formulation, and packaging, you can expect them to hold up for a year, give or take. Unless it's moldy or rancid, an expired bath bomb may not cause any harm. However, it might not dissolve or create the desired effervescent effect anymore.     What to Look for When Buying Bath Bombs?   Ingredients When browsing bath bombs, be sure to look carefully at the ingredients list. As Ross explains, they combine wet and dry components to cleanse the skin. In addition, they could include softening agents, which will make your skin feel extra soft after a bath. Cleansing and softening ingredients often include sea salt, Epsom salt, baking soda, clay, matcha powder, oat flour, glycerin, and coconut oil. Many bath bombs also moisturize with shea butter, cocoa butter, and plant oils, such as jojoba, safflower, sweet almond, sunflower, hemp, and meadowfoam.   Scent One of the most important considerations of a bath bomb is the scent, as they're often formulated with aromatherapy in mind. Some invoke a calming, peaceful ambiance, while others are more refreshing, rejuvenating, or invigorating.   Size/Quantity Bath bombs come in various sizes, ranging from about 1.5 ounces to roughly 7 ounces. With smaller fizzies, you may need to use two or three per bath, whereas larger options offer a hefty dose of cleansers, skin softeners, and aromatherapy.