The answer to this depends on how you use your computer, how knowledgeable you are about potential security threats, which email service you use, and so on.
- Some people definitely need security software
- Some people do not need extra security
At one time it was very easy to infect Windows PCs with viruses and other malware, and it was not recommended to use the internet without the protection of security software. I remember years ago when a friend bought a new computer and within five minutes of going online it was infected with a virus. The first two days with their new computer was spent cleaning up the viruses on it. They weren’t happy.
However, three things have changed:
- Windows 10 is more secure than previous versions of Windows
- Windows Defender is better at detecting malware
- Many email services block malware attachments
I have two computers running Windows 10 and one runs the normal release version and the other is a test computer on which the Windows 10 beta is running. The beta PC has been running for a year and it has never had any antivirus or other security software installed.
The PC running the release version of Windows 10 has had antivirus software installed. It had software from Panda Security and lately it has been running Avira. It is mainly used to test security software and like the beta PC, it doesn't really need it.
The Windows 10 beta PC has never had a virus or malware infection, even though it has had no security software other than what is bundled with Windows. It has Windows Defender and that’s it.
Maybe I have just been lucky. That is certainly a possibility, but let’s take a look at the results from virus experts AV-Test. In the AV-Test April 2016 antivirus test several products get perfect or nearly perfect scores. If you sort the list by protection then Windows defender is second from bottom.
This looks bad, but clicking a security product in the list reveals more information. For example, out of 22,795 samples of widespread and prevalent malware discovered in the previous four weeks, 99.7% was detected in March and 99.8% in April by Windows Defender.
Of course, it only takes one virus to infect a computer, but even the best antivirus programs often don’t detect 100%. Avast, which came at the top of the protection league table detected 99.9% of those samples. That’s just 0.1% more than having no security software installed.
This isn't the whole story and there are other tests, such as zero-day malware attacks and Windows Defender isn’t as good as Avast here, but for basic protection against malware it does a pretty good job.
AV-Comparatives is another antivirus software testing company and it regularly performs a real-world protection test. In the AV-Comparatives May 2016 test results Windows Defender did quite well. It wasn’t perfect, but it detected around 97-98% of viruses. What is shocking is that some security software actually reduced the number of malware samples detected. Check out the chart, they made security worse!
Security software (usually) increases protection from viruses and other malware, so if you want the maximum protection then Avast, Bitdefender, F-Secure and others will do the job.
However, Windows Defender and Windows 10 are much more secure than older versions of Windows and may be sufficient for some people. Especially if you:
- Avoid wares sites, download sites, pirate software
- Use an email provider that blocks viruses, like Outlook.com and Gmail
- Learn to spot bad emails with phishing and other bad links
- Use your common sense and don’t install dodgy software
- Get software from the Windows Store
I always recommend using antivirus software on Windows PCs because I know people download bad software, they open email attachments, and they click bad links in scams and phishing emails.
Security software (mostly) protects people from doing things they shouldn't. Bear in mind that other people that use your computer might not be as knowledgeable or as sensible as you, so you might need security software for them, even if you do not need it.
I don’t do risky things on my PC and that’s why my Windows 10 beta PC that has never had security software is running just fine. My main PC is running Malwarebytes Anti-Malware in addition to Windows Defender, but that’s mainly because I worry what other people do on it.