Duck hunting I do. I just bow hunt normally in the woods so I rarely do. Usually just use my rangefinder that has a little bit of zoom for turkey hunting but sometimes I do carry along my binos.

10x42's on the bino X-shoulder straps, 100% for as long as I remember. (Do not use them for turkey hunting though)

You asked about where size and performance crossed over. In my opinion, I wouldn't carry 25mm. Too small and low brightness. If 42mm size are bothering you,
Look into the 32mm size. Maybe something like this:

http://www.vortexoptics.com/product/vortex-diamondback-8x32-binocular

Every hunt. Never forget my binos. Ever.

10x42's everytime I hunt.Got the shoulder straps and I never know they're there.I will turn around and go back home to get em if I forget to grab em.

I'd feel naked without them.

I never owned any. About all the places I hunt is thick. None of them big green fields for me to shoot deer in. I suppose I could see the deer a little better but couldn't shoot till it got in a lane.
50 yards is a long shot a lot of times

All the time.

10x42 I do not and will not hunt without my binos.

Absolute necessity for me. My eyes suck. I carry 8x32 Zeiss Conquest binos when i'm in the woods. Have 10x42 Zeiss Victory binos for open fields or if I climb a tree looking over a clearcut.

the compact 8x20 or 10x25 binos are a waste of time and money. You will lose visibility in low light way before shooting light is over. I have a pair that were given to me and I think I paid too much...

Yes every time with a set of shoulder straps.

Not when I'm bow hunting , No need for extra weight. besides, i hunt in areas so tick I couldn't see much anyway. during the rut with a gun yes, I always carry them . I will say during the rut if you hesitate a cruising buck will be gone. I know guys hat have screwed with bino's and missed chances at trophies.

Always

I carry zeiss 10x42 every trip.

That's the safe way to check something out that looks like it "might" be a deer or hog or coon or whatever. You don't use your scope for verifying a target.

Me

I have some nice 10x30s which I think are perfect

I carry 8x30's using a bino harness that keeps them snug against my chest. Never know they're there til I need them. Hate to be without them in the woods.

They are in my bag and I have started using them more then I used to however I rarely use them in bow season or if I'm in a tight spot where I can only see 50 yards or less.

Every time