Default Mobile Security Constantly Running A Good Idea?

Just wondering from other users. Do you prefer to keep your mobile security such as avast always running or do you only run it periodically to scan for virus/malware here and there?

I'm wondering cause mine is greenified right now but is it better to just always run it and sacrifice a tiny bit of performance?

Sent from XT912
[AOSP/4.3] [ROM] Eclipse v5.1 build 6 spyder