One of the key differences between a professional penetration test and "amateur hacking" is exactly this: a defined, repeatable methodology. Two standards I always introduce in my pentest courses are PTES (Penetration Testing Execution Standard) and NIST SP 800-115.
PTES is more hands-on and practitioner-focused, while NIST SP 800-115 is more formal and documentation-heavy, commonly used in enterprise and compliance-driven projects. Knowing both demonstrates technical skill and boosts your professional credibility with employers.
A solid resource comparing both standards in depth:
Top Penetration Testing Methodologies (IBM): https://www.ibm.com/think/insights/pen-testing-methodology
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