The thing is Nails you are getting advice to install programmes from people who are not running w10 or defender. I can understand wanting enhanced security with the old w7 or even xp. But if you had just purchased a car with disc brakes and abs would you fit an anchor or parachute "just in case"?
// Is Windows Defender sufficient and good enough?
To be honest, Windows Defender only gives baseline protection, which means, it is only good enough for users for regular day-to-day surfing.
For those who mainly use social networks and may download the occasional file here and there, Windows Defender should be just fine.
If you download a lot of torrent related files from the web, then we doubt Windows Defender would provide enough protection.
Personally, I prefer to use Windows Defender than the other free programs out there, because it doesn’t pop up out of anywhere, and never asks me to spend my money to upgrade to a better service.//
http://www.thewindowsclub.com/is-windows-defender-sufficient-enough-windows-10
The only other security set up I would considerer is Malwarebytes, and only then if I was intending to use risky sites or link up with risky people on social media.