A good return on advertising spend (ROAS) is generally considered to be a ratio of 4:1, meaning that you generate $4 in revenue for every $1 you spend on ads. However, this is not a fixed benchmark, and the ideal ROAS can vary based on factors like industry, profit margins, and campaign goals. For example, businesses from some industries, like e-commerce and retail, may aim for a higher ROAS due to thinner profit margins and more focus on sales.