I spent a great deal of time dealing with Virus and Spyware but to me anything that should not be in your pc is infection whether it is a virus or spyware.
Infection come in many forms but mostly coming via internet and primary via browser.
Infection prevention is the key to not get infection! If you don't get infected in the first place then you don't have to spend time to clean up but that is not to say you don't need any form of defending your pc from infection.
This subject is a huge topic to discuss but I just focus on just Windows environment to keep this post short.
In Windows there are many free and none free anti virus/spyware solution and to me the best solution is something should be mostly invisible and small foot print but it should be "free"
I have use many anti virus/spyware like Norton, AVG, McAffee, Spybot, etc but they are taking too much load on the pc and it seem you have to buy a very expensive and powerful pc just to have these run on your pc to have the protection.
It is interesting that everyone has their own preference on which anit virus/spyware they like but my personal preference are as follow:
Microsoft Defender
Microsoft Security Essential
Microsoft fixIt
Glary Utilities
There is worth mention for a none free solution is Sophos.
The above solutions that I mention it takes nearly nothing on the pc and if I need to do upgrade or update it take no time at all and do periodical scanning.
The best of all they are mostly invisible and stay out of the way most of the time.
But the best still is be aware of what you are clicking and avoid the infection in the first place!
It is getting too long so I will stop here!
Thanks for your time.