Penetration testing is an essential security practice that assesses vulnerabilities in systems, networks, and web applications before attackers can exploit them. It involves gathering target information, identifying entry points, attempting to break in either virtually or for real, and reporting findings. Penetration testing should be done regularly to identify issues that vulnerability assessments and security tools may miss, as hackers develop new techniques daily. It is important for organizations of any size to conduct penetration testing to protect their business continuity, save money, and comply with regulations like GDPR.