Question [Q] Safestrap 3.65 back up getting ready for new update

I just installed safestrap and I want to understand how this works.
I backed up the stock system. I checked the first three including cache at the top. Not sure if that was correct. It opened and the cache was not checked so I checked. Now if I get an update to my phone will it save the root in safestrap? Do I need to select anything else in the options menu before backing up?
Or do I need to unroot my phone then download the new update then restore from safestrap?
I like to understand the apps when I install them on my phone. Right now because the phone is new I am going to use the OS stock. Down the road I might put in another OS like I did on my Galaxy Nexus that I loved.