What is the best free AV software, Bitdefender or Avast?

People really do not get it when they look at tests. The tests may show Defender having a 0.4% higher risk, but if you looked at results, you would almost certainly find result was in a very obscure and rare virus. Not only that, new viruses come along all the time, and there is no guarantee a tool with marginally higher score will protect you. Indeed, many people only update 3rd party AVs periodically. Defender updates daily.

In the end, it is bad user practice that is by far the biggest risk.

People who use a tool because "it has the best score" get lulled into false complacency.

It is a bit like driving a car with ABS brakes. We know ABS brakes work better in icy conditions BUT nothing works on pure sheet ice, and I am anazed how many people have become over reliant on ABS brakes and drive too fast and/or too close to cars ahead in poor conditions.

I use Bitdefender Total security - unlimited devices , which I am willing to pay for, several reasons for this ... It has been consistently at or near the top of the various charts produced for as long as I can recall.

It also provides a set of complementary tools over all my devices PCs, Laptops, Phones, and Tablets, so protects all possible entry points from infection.

It is controlled from a central location, that way I can check and update protection simply - If I purchase a new phone I can log onto my central control (the minute I have internet access) and it's protected before I leave the store

It's currently updated hourly to catch issues quickly and includes good heuristics detection for zero day issues.

To expand on your ABS analogy which I fully agree with, If you are planning or possibly going to end up driving on sheet ice, it's a good idea to carry snow/Ice chains or even fit studded tyres. You need a layered approach that meets your needs, and that is thought of and planned, before it happens, ( It might even prevent our current UK total stoppage due to winter weather that a lot of areas of the world would laugh at )

Recommendation

For someone working on a budget I would suggest that you run Windows defender and a weekly scan with Adaware and Malwarebytes to cover everything - also get to know and try to use the protected folders feature of Windows 10 (It's a PITA but it adds a lot to any security plan)

Total cost of this package is $0

If you have a little cash on hand I would also suggest that you look at regular backups to an external drive that is kept disconnected when not in use I use Aomei Pro but the Standard version will suit home usage better. another option is the forum favorite Macrium Reflect the software is free but you may need to purchase suitable drive or convert an old unused drive

Tonyb said:

hmm windows defender is it enough in this day in age one wonders .

In this day in age, NOTHING is enough, due vigilance is still and always will be best option. It's like expecting seat belts and air bags to protect you 100% and go slamming in 18 wheelers because you didn't see them.
It may be even worse than that, with all this internet connectivity, you better expect and be ready for a tree to jump out in front of your car.

Well I have seen at least 1 post here of a member get bitten running WD... if in doubt go by what the experts suggest..not by Tom, Dick and Sally...

xrobwx said:

In my opinion and the opinion of many, many others across the professional technical community is that Microsoft's own Windows Defender since version 1709, is a new and improved and very robust Antivirus. I would even say it might exceed the 3rd party and paid for AV's in the fact it's fully integrated into Windows 10. What's new in Windows 10, version 1709 | Microsoft Docs scroll down to Security after clicking the link and get all the info on the new Win Defender you need.

I used to use Avast Internet Security but stop paying for it as Avast has turned into bloatware. I have been using only Windows Defender and it does the job. I can see no reason to pay for an AV.