Mule deer are one species where I pack all the optics. For me that's 10x42 Leica Geovid HD-B binos in the chest harness, 15x56 Swaro HD binos and the Kowa TSN 554 spotter. My buddy I hunt with has 8x42's and a Swaro STS80 spotter. Both of us have tripods.
I primarily use my 15's and he uses his spotter when we glass together. When we are separate my Kowa lets me zoom in to evaluate a buck if I can't see enough through my 15's. I rarely use the spotter while hunting, but use it just enough I keep carrying it. I use it much more scouting.
I'm always hunting muleys out of state in a place I have only scouted for 3-5 days. I'm realistic, if I see a mature looking buck with mass and a good frame I'm probably going to take him. I don't need to be able to see as much detail as some people looking for a certain score.