According to the text, mobile home park buyers are aware that operating expenses typically range from 30% to 40%. However, they may aim for a higher ratio of 40-45% for optimal expense management. The average operating expense for a mobile home park is usually around 35-40% of the gross income. This includes utilities, trash service, and maintenance costs. Mobile home parks tend to have lower turnover rates compared to apartments. For apartment buildings, a good operating ratio is between 35% and 45%. Additionally, mobile home parks have higher profit margins due to their operating expenses being around 30%-40%.