B2B SaaS companies are increasingly adopting usage-based and hybrid pricing models, with nearly 39% now primarily using usage-based pricing, especially in sectors like AI, fintech, and infrastructure. This shift demands a robust billing infrastructure to handle complex contracts, flexible pricing, and accurate metering, as manual processes often lead to errors and inefficiencies. The article outlines best practices for SaaS billing, emphasizing the importance of technical accuracy, automation, and architectural clarity, while highlighting platforms like Lago that facilitate efficient billing at scale. Challenges such as managing diverse pricing models, ensuring real-time metering, and complying with global tax regulations are addressed through automation and integration with CRM, ERP, and analytics tools. Continuous auditing and optimization of billing workflows are also recommended to maintain accuracy and trust, ultimately leading to faster time-to-cash and improved customer satisfaction.