Merchant is a fan of wood for bathtub trays. "I love the warmth it adds to contrast with the white finish of most bathtubs," she tells The Spruce. "Wood tends to last a long time, and it ages nicely." Many tub caddies are bamboo, which isn't technically wood but looks just like it. Since the shoots regrow very quickly after harvesting, it's considered a renewable resource. The material is also naturally water-resistant and quick-drying. You can also find options made of porcelain or stone, which hold up well in wet environments. (That's why you see these materials in bathroom floor tiles.) Stainless steel is another good option, as the metal is highly durable and rust-resistant.