Legions Imperialis Tactics: Minimum VS Maximum Formations and Detachments

In todays tactics video, we discuss the pros and cons of smaller or larger detachment and formation sizes for legions Imperialis.
Small formations like a minimum sub cohort could be as cheap as 130 points, while a full Demi company can cost over 2,000 points with all the bells and whistles.

[@rathstar]

Ideally I think you need both large and small detachments. Large detachments are great to activate first and get lots of damage in on a key target for a single activation. Small detachments are great for waiting out the enemy to move key units you want to target, eg. waiting for a vehicle to move to infantry can charge it and it can't get away. Small units are also useful for getting objectives in locations where you won't really be able to fire on the enemy due to terrain (no point wasting a large firepower unit for this task). While some of the fast attack marines units are great form small detachments I also like 5 bolter marines in 2 rhinos giving 2 activations for 55 points, and will marching+dsembark+March/Advance can move some distance in a single turn.
Looking out for points discounts as you said can change the decision, eg. Kratos at max size drop 75 points each to 58.3 each, Sentinals drop from 17.5 to 12.5 each at max size. Another points discount is if you include specialists with basic drops, eg. you save 10 points by including missile marines with basic bolter marines. While tactically this doesn't work, eg. bolter marines slowing down assault marines and preventing terminators from deep striking they can be great for giving the specialists ablative wounds, for example missile marines and ogyrns. Cheap ablative wounds are also great for aggressive units that will take casulaties early, eg. infiltrating missile marines and aggressive ogryns.

[@EagleSpireGaming]

@@rathstar very well said, and don’t forget the formations of legend as a third way to save points.

[@AyeDubbleYoo]

It's a bit unfortunate at low points when your whole army could be one formation, and you have to deploy it all at once. Had that at 1000 points but I reworked it to include a Skyhunter Phalanx as well.
Even just two formations feels a lot more flexible to deploy, and of course you get the Outflank bonus on the fast attack stuff.

[@EagleSpireGaming]

@@AyeDubbleYoo yeah, you need some way to get an idea of where your opponent is playing. Alternatively, at low points like that, maybe play with a fog of war like mechanic, where you and your opponent deploy in secret.

[@davidwasilewski]

Spend a quarter of your points on small detachments, a half on medium and a quarter on large. Flexibility. Combined arms!
Obviously this is all somewhat dependent on the size of game you’re playing.

[@EagleSpireGaming]

@@davidwasilewski we might need to adjust these numbers a bit. 1/2 of a 3k game is 1,500; and we’re spending that on medium detachments. 1/4 is 750, and that’s our value for small and large. So our largest formation is 750, and we have twice that for medium formations. This means we need to break the medium formations into 3 formations minimum, of 500 points each. There’s just not a lot of room for tanks when we break it up this way.
Edit, I realize we both said detachments, but I was thinking about formations the entire time.