Rule A.1

 A.1 on dice: this rule says that “players may also find it beneficial to get in the habit of rolling three dice,” since there are many situations in the game for which a subsequent dr is necessary. Rolling three dice in advance would speed things up. But what are these situations? The rulebook mentions six.

5.132: missing a vehicle when the location is overstacked. If you fire at a vehicle, you might miss. That goes without saying. But if that vehicle is in a location crammed full of other vehicles, you might just hit another one by accident. You might even hit a friendly. The rule here is a little weird, because the possibility of hitting a secondary target depends on whether your opponent’s side is overstacked, but the subsequent dr takes into account the total number of vehicles in the location, including your own. Basically, say guy has three vehicles in a location. If you miss your shot, you might hit another one as long as your roll was no more than two over your to-hit number (two extra vehicles, ya see?). But then the subsequent dr takes into account the total number of vehicles. So suppose you are firing into a maelstrom of metal and you had a truck in the location, too. There are four vehicles there! If the subsequent dr is less than four, you hit something; random select it.

            There’s a little more nuance to it, so read the rule, but here it is. If you are firing into an overstacked (vehicularly speaking) location, roll three dice.

7.309: unlikely kills. A natural 2 DR on the unarmoured vehicle line always has a chance of doing some damage.

9.74: Random SW/Gun destruction. Whenever you roll a KIA result against a unit possessing these things, roll a dr on the same column; if you get a KIA or K result, then the thing is either destroyed or malfed. That’s life. But would you really bother rolling three dice every time just for this? I mean, I guess you could. Just roll three all the time.

11.13: the fate of SW in close combat—this is similar to the rule above; basically, whenever a unit is taken out in CC, there is actually a pretty good chance that the SW dies, too. You make the roll.

11.501: unlikely kills in close combat vs. a vehicle. Pretty much the same thing as in 7.309.

24.1: trying to place smoke up a hill. Roll a subsequent dr: there’s a 50-50 chance the smoke grenades roll back down the hill on you. Ha!

 I've also heard of people always rolling a third die for rate of fire.That way you might roll a ten (5,5) or something, but still keep rate (5,5,1). I have no idea how widespread this is, honestly. I've never done it, I don't think.