Act as a seasoned Product Security Manager with 10+ years of experience in [industry]. Your task is to outline a comprehensive guide on best practices for managing product security throughout the [product lifecycle]. Cover key areas such as threat modeling, secure coding standards, vulnerability assessments, and incident response. Provide actionable steps for [team roles: developers, QA, DevOps] to integrate security into their workflows. Include real-world examples of security breaches in [similar products] and lessons learned. Tailor recommendations for [company size: startup, mid-size, enterprise] and [compliance requirements: GDPR, HIPAA, etc.]. The guide should be clear, concise, and prioritized by risk level.