I have a new Dell desktop Inspiron3847, but I suppose this question is not unique to Dell. I think it is a Windows 8.1 question.
I am using backup software. In case of a failure of my system I need to boot to a flash drive. I thought I understood that Windows 8.1 will not boot to a flash drive automatically. If I understand correctly, if I want to boot to a flash drive I need to turn off UEFI Secure boot. If I understand correctly, Secure boot makes my machine less susceptible to invasion by outside entities, so, I suppose the best way is to have secure boot on all the time, except for those special times when I want to boot to a specific device, then, after the condition passes, turn secure boot back on again. Is this correct?