Designing a high-load database architecture can be challenging, and organizations often make common mistakes that lead to infrastructure cost mismanagement. These include lack of experience with high-load projects, suboptimal technology stacks, relying too much on the cloud, and falling into the "free money trap." To avoid these pitfalls, companies should invest in managed service providers or self-serve solutions paired with DevOps expertise for better performance optimization and cost savings. Additionally, startups should consider infrastructure credit as real money and spend it carefully to prepare for growth and increased operational costs.