Everyone has their own preference so I can't really say what the most common way is but it is a good way to start out; it helps make things simpler until you get the hang of using the mil dots.
The way I use a mil dots depend on what kind of shooting I'm doing. If I am shooting at paper then I use the knobs to adjust my aim point for elevation and I may or may not use the knob adjustment for the windage. If I take a shot at a animal and I see that my point of impact was 1 mil low and a half mil to the right I will use the mil dots to change my POA so that I can make a quick follow up shot rather than taking the time to adjust the knobs.
As for how many clicks you adjust at any particular range, well that requires a little math. Your scope knobs are setup for 1/8 MOA per click. One MOA is equivalent to a different number of inches at different ranges but the change in inches is linear, there is a specific amount of change for a specific distance.
1 MOA at 100 yards is approx. 1 inch (closer to 1.05")
1 MOA at 200 yards is approx. 2 inches
1 MOA at 300 yards is approx 3 inches
and on and on...
So at 600 yards one MOA is about 6 inches (it's actually closer to 6.28 inches but we can round off unless you are shooting for score).
Your scope is setup so that you have 8 clicks for one MOA, regardless of what the range is.
So at 100 yards 1 MOA is one inch, divide one inch by the 8 clicks it takes to move one MOA and that means each click is equivalent to 1/8 inch at 100 yards.
At 600 yards 1 MOA is about 6 inches, divide 6 inches by the 8 clicks it takes to move one MOA and that means that each click is equivalent to about 3/4 inch at 600 yards.
So;
Yards
100 - 1 click = 1/8 inch
200 - 1 click = 1/4 inch
300 - 1 click = 3/8 inch
400 - 1 click = 1/2 inch
500 - 1 click = 5/8inch
600 - 1 click = 3/4 inch
There is an easy way to remember this.
100 yards = 1/8 inch
200 yards = 2/8 inch
300 yards = 3/8 inch
400 yards = 4/8 inch
500 yards = 5/8 inch
600 yards = 6/8 inch
Notice the correspondence between the first number in the range and the numerator of the fraction (the top number of the fraction). That makes it easier to figure out the number of inches per click at weird ranges. A range of 732 yards would mean that each click is equivalent to 7.32/8 of an inch. At 1000 yards each click is equal to 10/8 of an inch or about 1.25 inches per click.
So if you are zeroed at 100 yards and your target is 450 yards away you know that each click is 4.5/8 of an inch, that's just little more than a half inch per click. If you need to compensate for a 20 inch drop then you would need to add something less then 40 clicks, maybe around 30 to 35 clicks.
You can sit down and do the math or just guess like I just did, with practice you will become familiar with your weapon, scope, and cartridge and that guesstimate of 30 to 35 clicks will get more precise. I recommend to always add a little less adjustment then you calculated because most scopes don't track perfectly and you can always adjust a little with a different POA.
okay,so if I understand this correctly, almost everyone "zeros" the scope at 100yrds at max power unless the manufacturer requests other wise.
Then, sounds like most shooters prefer to use the mildot's to adjust their POI with a hold over method vs just changing it directly on the scope itself?
But some will tweek their scopes to known distances since the data would be roughly the same regardless of what they are shooting at for target at 100,200-700yrds etc. for example...lets say I know that I need to bring it up 20 inches due to the BCD for the round I am using from the 300-400, I can just estimate with the Mils OR put the clicks up 20-24 using my scopes 1/8 MOA adjustments to get near the target.
so it would sound like the more proficient shooters like to just use the mildots since they have the practice behind them and only utilize the MOA when the environment calls for them to slow down and find a general area.
My knobs adjust at 1/8 MOA (not the standard I know)
So do these sound right for adjustments made directly on the scope itself?
Yards
100 - 1 click = 1/8 inch
200 - 1 click = 1/4 inch
300 - 1 click = 1/2 inch
400 - 1 click = 3/4 inch
500 - 1 click = 1 inch
600 - 1 click = 1 1/8 inch
Thanks guys.