When to declare a unit is using deep-strike

[Tame]

When should I declare that a unit is going to be using deep strike ? When the unit is held in reserves, or when I actually use the deep-strike ability to place them after having rolled for reserves ? The main question behind this is, can I keep a unit in reserve and choose at the last moment whether they enter using my board edge or deep-strike in ? Outflanking units must be declared before (p. 94) but nothing is said for Deep Striking in the BRB...

[BladeEncarmine]

BRB, page 94 under the heading "Preparing reserves", 3rd paragraph:

 

If units in reserve have the "deep strike", "scout" or "inflitrate" rule, the player must declare to his opponent, during army deployment, whether they are going to use their special rules to deep strike/outflank or they are going to enter from his own table edge when they become available (see Arriving from Reserve). This decision may not be changed later.

 

So no deepstriking if you feel there's a weak point later in the game if you said a unit is coming off the edge.

[Tame]

Ah, thank you. I have been reading this countless times, always missing that paragraph !