I would not advise what I do unless you are experienced, I agree.
I also do not use an AV on this computer, running Windows7 SP1.
I don't visit Porn sites ever,as food is more important at my age.
I run on demand scans regular and use Windows inbuilt tools.
All my other PC'S all run AV's and all updates installed.
I did check for updates on this rig for interest, and including Office updates over 2 GIGs of updates waiting.OMG.
I have noticed that immediately all updates are installed my Computers slow down somewhat.
Not a lot but can notice the difference immediately.