Unless it's an extended trip, I generally don't decide on my gear until the evening before the outing. Depends on the weather, my mood, the specific
location, what type of film I have packed in what kit, what kind of load I want to carry (I often deliberately keep my kits quite heavy for training purposes - it sure beats working out like a rat on a treadmill in some stinky gym, regardless). Often I like to carry the 8x10 one weekend up some
steep hill, then alternate that with a minimal Nikon the next weekend for the sake of a fast pace, to exercise muscles differently. But then there are
those seasons when color is particularly intriguing when I need to ration 8x10 color film very carefully due to its expense, and default into 4x5.
Right now, I'm getting in shape for the summer backpacking season in the high country, so the heavier the pack, the better. All that being said, once
I'm actually in the darkroom, the bigger the film, the better. I'd rather print from sheet film any day rather than flimsy 120 roll film or itty bitty 35mm. But it's just that certain types of shots are more easily had with them lil' buggers. My 6x7 sure hit pay dirt last weekend. Just didn't have the
time to put in the mileage plus fiddle with the 8x10. So I threw in two full 6x7 kits to keep the pack heavy.