From the perspective of a business? Probably the age you start buying their products. Not to be too cynical, but I doubt many companies give a damn what people

From the perspective of a business? Probably the age you start buying their products. Not to be too cynical, but I doubt many companies give a damn what peoples opinions are, if those people aren’t buying their products, or if there isn’t a creditable threat those people will start to influence the opinions of people who do buy their products.