The idea was that your opponent had to kill one more model in order to get you below half strength, whereas squads with uneven number of models (3, 5, 7 and so on) was sub-optimal. Your opponent had to kill 4 members of a squad of 6 models to make it non-scoring. If you'd only taken 5 models, he would only have to kill 3.
...and then 5th edition came along
This is no longer the case in 5th, but many people seem to think even numbers are better. They are not.
Consider a unit of four models. If they are Troops, they are scoring to the last man. If they are not, then the number of models doesn't affect their scoring status at all. The only impact number of models has (other than being harder to kill and doing more damage), is whether they take morale checks from a certain amount of fire power.
A unit of four models must take a Morale Check if it loses a single model. This can be disastrous, especially if the unit type is Jump Infantry, Bike or a similar fast type which retreats 3D6". It may flee off the board due to a single casualty!
Always take 5 Necron Destroyers, never 4
Fritz over at Return of the Star Gods has an excellent Necron Destroyer tactica on his YouTube account. There is only one area where I feel he makes a mistake, and that is the squad size of his Necron Destroyer units. He takes 4 models. This unit may give away a Kill Point from a single shot, even before We'll Be Back-rolls, which makes it brittle.
Ld 10 is all good, but you will fail it from time to time. For the cost of a single model more, your opponent has to divert twice as much firepower before a Necron Destroyer unit of 5 models has to take a potentially devastating Morale Check.
It is pretty clear that 5 Destroyers are superior to 4, but considering how much firepower it takes to take out two models of a T5 Sv3+ unit, there is really no reason not to take the full compliment of 5 models.
Optimal squad sizes
To conclude this article, I'll just go ahead and list the optimal squad sizes in regards to when the unit will be taking Morale checks. The unit is as brave as possible for the least amount of points, so to speak.
Size - Tests after how many casualties?
- -
- 1
- 1
- 1
- 2 <- Optimal
- 2
- 2
- 2
- 3 <- Optimal
- 3
- 3
- 3
- 4 <- Optimal
- 4
- 4
- 4
- 5 <- Optimal
- 5
- 5
- 5
- 6 <- Optimal
