If you are asking how often you should run network penetration testing, the practical answer for most businesses is at least once a year. But that is only the starting point.
Your network is not static. New laptops get added, remote access changes, cloud platforms evolve, software is updated, and staff join or leave. A penetration test gives you a real-world view of how an attacker might exploit those changes.
Northern Star’s own Penetration Testing makes this point clearly: traditional assessments only show a point-in-time snapshot, while regular testing helps you stay secure as your environment changes. The wider UK picture supports that level of caution too. The government’s Cyber Security Breaches Survey 2025 found that 43% of UK businesses identified a cyber breach or attack in the previous 12 months.
Why once a year is the minimum
For many organisations, annual testing is a sensible minimum because cyber risk does not stand still for long. The NCSC describes penetration testing as a core tool for analysing the security of IT systems, while also warning that it is not a magic bullet on its own. In other words, it is valuable, but it works best when it forms part of a regular security programme rather than a one-off exercise.
Annual testing also fits with the rhythm many UK businesses already follow for cyber assurance. If you are working towards schemes such as Cyber Essentials, it is worth noting that Cyber Essentials certification must be renewed every 12 months, and government guidance also notes that certification reflects compliance at the time of testing only and can become outdated much sooner if patching and secure configuration slip.
When once a year is not enough
A yearly test may be fine for a stable, low-change environment. But plenty of businesses are not in that position. If your systems are changing often, or if your risk profile is higher, testing more frequently makes more sense.
You should consider more frequent testing if you have:
- Multiple offices or international locations
- A growing remote workforce
- Sensitive client or financial data
- Regular infrastructure or firewall changes
- Third-party suppliers with network access
- Recent migrations to cloud platforms
- New customer or insurer security requirements
That is especially relevant if you rely on services such as Cloud Services / Office 365, Migrations, Consulting, European IT Support, or Global Support and International Projects, because every change in infrastructure or access can alter your attack surface. Northern Star’s service pages and recent penetration testing content both emphasise that regular reviews matter when networks evolve.
Situations where you should test straight away
Sometimes the question is not whether to wait 6 months or 12 months. Sometimes you should test now.
After major infrastructure changes
If you have changed firewalls, reworked VPN access, moved services to Microsoft 365, merged networks, or rolled out new sites, a fresh test is usually worth doing. A new weakness often appears during change, not because the project was poor, but because complexity creates blind spots. That is one reason Northern Star describes regular testing as more valuable than relying on a single snapshot.
After a cyber incident or near miss
If you have had suspicious login activity, a malware scare, exposed credentials, or a phishing-related compromise, a penetration test can help you understand what else an attacker might have been able to reach. It should sit alongside wider controls such as dark web monitoring, secure IT defences, and strong endpoint protection such as EDR.
Before compliance reviews or major client onboarding
If a customer, partner, or insurer is asking hard questions about your security posture, recent evidence matters more than a test you ran a long time ago. A penetration test can help show that you are actively identifying and fixing weaknesses, especially when combined with broader IT Support and Management and Hardware and Software controls.
A practical testing schedule for most businesses
A simple way to think about it is this:
- Every 12 months as a baseline for most small and mid-sized businesses
- Every 6 months if your environment changes regularly or your risk is higher
- Immediately after major changes to infrastructure, access, or cloud systems
- Immediately after an incident or credible security scare
- Before important audits, tenders, or customer reviews where assurance matters
That schedule is more realistic than choosing a fixed date and ignoring what happens in the rest of the year. It also reflects the fact that penetration testing should be tied to change and risk, not just to the calendar. The NCSC’s guidance and government Cyber Essentials renewal rules both support the idea that assurance ages quickly if your environment is moving underneath it.
What penetration testing should sit alongside
Penetration testing is valuable, but it should not carry your entire security strategy on its own. It works best when it supports other controls, including security services, anti-phishing awareness, ongoing support, and practical remediation of the issues that testing uncovers.
Northern Star’s recent content around common network vulnerabilities pen tests uncover makes this especially clear: the value is not just in finding flaws, but in fixing the right problems before someone else finds them first.
Final thought
So, how often should you run network penetration testing?
For most businesses, once a year is the minimum sensible answer. If your environment changes often, your data is sensitive, or your customers expect stronger assurance, every 6 months is usually a better fit. And if you have been through a major system change, or had any kind of cyber incident, it is wise to test sooner rather than later.
If you want a clearer view of what frequency makes sense for your business, speak to Northern Star. Their team can help you review your current setup, identify where the real exposure sits, and plan a penetration testing schedule that matches your risk rather than relying on guesswork.
