A comment made in a recent post has prompted this Easter special for you all. Sacrificing and sacrificial units is a misnomer, this generally isn't their sole purpose or role. Certain units such as designated bubble-wrap are built to generally die for the 'greater good' of the army though they do contribute to the army in other ways (generally firepower whilst wrapping the army). Other units commonly expected to die such as sacrificial melta aren't actual sacrifices, they are simply called that because they are expected to die once their role is done (think Fire Dragons outside of a transport). Instead, sacrificing units in-game is a role any unit can perform and it's not about being useless but rather by dying and delaying specific aspects of your opponent's army (or simply delaying), the unit is generating greater benefit for the army as a whole.
This is really important to consider in list building as if there are any units which are too valuable or center-pieces of your army, they aren't going to make good sacrifices and if there are too many of these, your army isn't very flexible (not to mention if the army doesn't work too well without those units, what happens when those units are killed?). This is a core concept of MSU armies as there are multiple units so losing a squad or two doesn't matter in the grand scheme of things; there are more where they came from. In a more 'traditional' army this is still very possible as long as you sacrifice correctly. So let's take a look at that and see if we can't shed some light on it.
In the grand scheme of things winning isn't about what you have left on the table but rather if you've accomplished the mission parameters better than your opponent. In most 5th edition games this puts a premium on your Troop units as only they can score and thus makes them less desirable as sacrifices. Otherwise all units should pretty much be considered equal as sacrifices if the situation is correct.
For example, a very expensive unit of Incubi can move laterally to block a potential charge on a Kabalite Warrior unit by a unit of Lash Whip Tyranid Warriors. The Tyranid Warriors are likely to wipe the Incubi out but by protecting the Kabalite Warrior unit, the Dark Eldar player is therefore able to hold the objective behind them in the next turn. In this case the Incubi are a good sacrifice as it allows the Kabalite Warrior unit to hold the objective. However, if this was early game this might not necessarily be the case (unless the Warrior unit is your last Troop) as the Incubi are more likely to have a significant impact during the game compared to the Warriors. If the Dark Eldar army has other Troops available keeping the Incubi alive could prove more beneficial down the road.
What this example highlights is two key points:
1) the cost/effectiveness/power of a unit doesn't matter when it is being used as a sacrifice, only whether or not the sacrifice is going to benefit your army overall
2) a good sacrifice can be a bad sacrifice depending upon the game turn and what else is left in the army
What this really highlights is sacrificing becomes a very fiddly art to nail down with words much like deployment. There are a multitude of variables which need to be considered but in the end you need to ask yourself this:
"Does sacrificing this unit benefit my army?"
If the answer is yes, then you should consider doing it whilst understanding the ramifications of doing so whilst if the answer is no you probably shouldn't. Makes it seem mind-boggingly simple doesn't it? This can generally be identified by understanding the opportunity cost of sacrificing such a unit. If using a squad as a screen for your army would stop multiple Dreadknights from charging your stationary tanks or more important units on T1, well that sounds like a pretty good trade-off to me. If that same unit is a scoring unit and you've only got two in your whole army though, the opportunity cost becomes too high and another unit used in its place.
Ultimately sacrificing is about keeping your army functioning for as long as possible. You'll lose the overall shape of the army as units get whittled away but by sacrificing units which are less important to army functionality, your army will continue to be effective on the tabletop for longer whilst good sacrifices make your opponent's army less efficient. Some units are going to be better sacrifices than others (i.e. transports after their cargo has been delivered) but ultimately every unit in your army should be capable of being sacrificed if the situation demands it to with the mission. If you find your army struggles with this during games perhaps you need to go back to the ground work of your army and tinker with your list.
