Welcome to Librarium Online!
I have this very n00bisch question about... you alreay know it: "reserves"
I know when you put you dred in a droppod they pop behind the enemy lines.
I know that your termies can teleport their asses "into the fray"
But I've seen games where tanks are also in reserves, and I just don't get why anyone would do that
Because when they come in it's on your boardedge.... And when you play against a shootie army, you wasted your turns not getting there. When you play against a assaulty army, you wasted your turn not shooting them.
Please clear this subject up for me. (I'm a new player so please, please don't tell the emperor i posted this )
Probably due to the mission special rules, not allowing vehicles to be deployed. So they are forced to start in reserve. If thats not the case, then I agree, there is no useful reason to do that.
You are confusing deep striking with reserves.
Reserves start off the table and join the battle after its start, comming on at the table edge within your deployment zone.
Deep striking is a method of deploying reserves (and occasionally other things) which allows the unit to appear on the table at a point of their choice, although not entirely accurate, fluff wise it is often - dropping from above, teleporting, tunneling, moving through sewers etc
But deep striking is only available to those units that have it in their codex, you will notice that with the obvious exceptions of skimmer vehicles capable of decending from orbit, or drop pod or other transportable vehicles, (eg dread) no vehicles have the ability to deep strike
Everything you have been told is a lie!
I had a Land Raider which had the ability to deep strike. It had 4 parachutes attached to it to enable it to float down to the ground.
I tested its survivability by hurling said Raider out of my top floor window and watched it plummeting to the ground.
Thinking the parachutes would do the job I nonchalantly walked down stairs and opened the door only to find my Land Raider in a thousand pieces.
That, boys and girls, is why vehicles don't deep strike
I can't say I've seen it all but I live for the things that keep me hollow.
if sentries are being used in the mission, the alarm is immediatly raised if you deploy any vehicles... or bikes