In my computer repair business, I am still getting W10 computers with all kinds of bad viruses when their Owner's completely rely on Windows Defender alone.
If they add a good antispyware program such as Malwarebytes (mentioned twice above), I still get infected computers. Some customers have tried SuperAntiSpyware, another well-rated program; but those programs together don't stop everything.
Of course it's up to you; but the old saw
"you get what you pay for", really applies to AV programs!
I disagree with both of my esteemed colleagues on this issue; I've been seeing this occur for the last 20 years ever since Microsoft decided to include an AV program built-in to Windows. So, regardless of what you read on the...