Heya,
I shoot a 5D classic for full frame. I use APS-C for everything else, as I want maximum pixels (mostly wildlife and macro). I use full frame for portraits basically exclusively, where control of depth of field and field of view is easier in tighter spaces and more isolation of subject when I want it. Also when I'm focusing manually, I'm using the 5D. I use APS-C for literally everything else, where thin depth of field doesn't matter, even landscape.
Very best,
:: My 
