Antivirus utilities distinguish themselves by going beyond the basics of on-demand scanning and real-time malware protection. Some rate URLs you visit or appear in search results using a red-yellow-green color-coding system. Some actively block processes on your system from connecting with known malware-hosting URLs or fraudulent (phishing) pages.

All software has flaws, and sometimes these flaws can compromise your security. Prudent users keep Windows and all programs up to date, patching those flaws as soon as possible. The vulnerability scan offered by some antivirus apps can verify that all necessary patches are present and even apply any that are missing.

Spyware comes in many forms, from hidden programs that log every keystroke to Trojans masquerading as legitimate programs while secretly mining your data. Any antivirus should handle spyware, along with all other types of malware; however, some include specialized components dedicated to spyware protection.

You expect an antivirus to identify and eliminate malicious programs, while leaving legitimate programs alone. What about unknowns, programs your AV can't identify as good or bad? Behavior-based detection can, in theory, protect you against malware, so new researchers have never encountered it. However, this isn't always an unmixed blessing. It's not uncommon for behavioral detection systems to flag many innocuous behaviors performed by legitimate programs.

Allowlisting is another approach to the problem of unknown programs. This type of security system only allows known good programs to run; unknowns are banned. This mode may not be suitable for all situations, but it can be useful in certain cases. Sandboxing allows unknown programs to run, but it isolates them from full access to your system, preventing them from causing permanent harm. These various added layers serve to enhance your protection against malware.

However, most top antivirus brands regularly run special promotions, significantly reducing their price per subscription (for example, Norton is currently offering a 58% discount, so you can get Norton 360 Deluxe for $49.99 / year*).

It’s worth noting that some cheap (and free) antiviruses don’t offer a decent level of protection, so while you may be saving money, you could put your devices at risk. That’s why you should only choose a trusted, low-cost antivirus with excellent security protections.