Here's a quick look at the information we've gathered on if and how much blaze orange you might need in the state you're hunting:

State Required? Rule
Alaska No Not required but encouraged.
Arizona No Not required but encouraged.
California No Not required but encouraged.
Colorado Yes 500 square inches of solid Orange or Pink, no camo must be worn above the waist including a hat. Required on rifle and muzzleloader hunts.
Idaho No Not required but encouraged.
Kansas Yes A hat and 200 square inches with 100 inches each front and back must be worn during firearm and muzzleloader seasons.
Montana Yes 400 square inches for hunter and anyone accompanying.
Nebraska Yes 400 square inches covering head back and chest must be worn during firearm seasons or while archery hunting during the late firearm seasons.
Nevada No Not required but encouraged.
New Mexico No 244 square inches must be worn while hunting on the Valles Caldera Preserve or any Military property. Otherwise encouraged but not required.
North Dakota Yes 400 square inches and hat above the waist.
Oregon Yes, 17 and under Hat or other garment must be visible from all directions.
South Dakota Yes At least one garment worn above the waist must be orange. 400 square inches above the waist is required while hunting any National Refuge.
Texas Yes On Public hunting lands including State, National Forest and Grassland 400 square inches with orange head gear and 144 square inches visible front and back.
Utah Yes 400 square inches must be worn if an any weapon hunt is open in the area.
Washington Yes 400 square inches above the waist during firearm seasons.
Wyoming Yes One or more upper exterior garments must be worn. No square inch requirement.