Does everyone keep track of HPs individually for "Orc #1" or do you sometimes use a shorthand system?
For years now I've used a system of "hits".
I define a hit as "5 points of damage". I track "half hits" which is less than 5 points, but not equal to 1.
A "one hit mook" then will fall when it takes one hit of 5+ points or when it takes two "half hits". Usually a "one hit mook" is a 1 HD creature, but not always. A tough orc leader might require two or even three hits to down. The HD is just a yardstick that helps me think about how many hits a critter aught to take before being defeated.
I usually use "X's" as the hits and "/" as half hits in my notes. Sometimes I'll mark monsters like so, using circles to represent the hits. Then I just mark through them with slashes or X's as the monster takes damage.
Orc 1 O, 2 O, 3 O, 4 O, 5 O, 6 O; Orc Leader OO
Does anyone do anything similar to this when running your games?