Best use of Rerolls

You know... I have said before that I think the best use of our rerolls is reroll of damage on DLs.
But I was wondering if it is actually true...
For example I thought about Heat Lances... how about rerolling their wound rolls? Coz if we get through the save, we have a free reroll on the damage, right? So we can get more rerolls through rerolls... even the wounding on 5+, which is 33% chance, becomes 66% chance with a reroll.
Any thoughts on this or other uses of rerolls?

The best reroll is the one that enable you to kill your threat when it needs to.

Dark lances makes great reroll, sure. But keep in mind that a blaster shot that finish a dangerous opponent on a "2" is far better that a lance shot of 6 on a new leman russ.

That said, the best reroll is for the reaper main gun.

Well Blaster rolls 2 damage on 66% of occasions. It does not "need" the reroll.
I am asking this question because analysis of the issue could help people recognize how many rerolls they actually need and when is the critical moment. Also it might breathe new life into aforementioned Heat Lances since they are actually getting very dangerous.

As a general rule, using re-rolls should be based on your likelihood of success with that re-roll. While the final result for a heat lance against T7+ may be 5/9ths with a re-roll, the actual chance for the re-rolled die itself to succeed is still only 1/3. You've got a 2/3 chance for that re-roll to be a waste, not just of the command point but of your re-roll capacity for that shooting phase.

If a Dark Lance rolls a 2, by contrast, you've got a 2/3 chance for the re-roll to improve the resulting damage output, and it will do so by a fairly significant margin. If it rolls a 1, you've got a 5/6 chance to improve the outcome and it's likely to increase it by several hundred percent.

In almost all cases, the correct use of the re-roll is on a poor damage roll or possibly on an early 2++ fail from an archon. Really terrible morale rolls are a valid re-roll target too. Maybe a really crummy advance roll if you're trying for a late-game objective grab or something. Misses and failed wounds are usually a poor use of the re-roll, though.

Reroll the D6 damage every time you need to. There is almost no situation this isn't called for.

Also reroll to seize.

Exactly. It does not matter if you reroll a 5+ success. You do reroll and double the chance whenever it might give you a tactical advantage.

@mynamelegend - you cannot reroll a Shadowfield by any means. Its in the description.
But... thats what I thought - reroll of hits is a terrible use unless using soulburner bombard or something like that, reroll to wound as of itself I agree, but in the particular case of Heat Lance... It might actually be worth it.

(You're right, shadowfields can't reroll, mea culpa)
It would be wise to re-roll wounds on heat lances... except the Heat Lance itself isn't worth it to begin with. HLs are a rather terrible weapon, and you'll probably do better building your army around Dark Lances. They'll wound more often, against quite a lot of targets twice as often, and they cost less.

"If a gun requires command points to maybe approach the utility of another, cheaper, more plentiful gun... Don't use that first gun" is a good rule of thumb.

aurynn wrote:

... even the wounding on 5+, which is 33% chance, becomes 66% chance with a reroll.

Mathematically that's not right.

Initially you'll be rolling for the 5+. That's a 33% chance, or 1/3. on the chance you don't roll a 5+, and instead roll lower, that's a 1,2,3 or 4. so 2/3 chance. Then you get another 1/3 chance of success with the reroll. where (2/3)*(1/3) = (2/9)

1/3 + 2/9 = 5/9

so a 55.55% chance of 5+ with the reroll. Still pretty good odds.

Well I did simplify it to the point of rolling 2d6 and getting at least one 5+, but its not that important to the topic.

@mynamelegend - true, but I hate spam... in units, in weapons, in anything. :-D Just because something is supposedly BIS, it does not mean you should not have variety.

I can't re-roll to Seize due to ITC tournament play, but the times I use the re-rolls for the most part is almost always a crappy D6 damage roll from Lance damage.

Never a reason to not reroll seize the initiative other than that damage or number of shots are usually the best use ... though a sslyths guardian roll would be useful

Mostly I have found them useful for damaging high wound targets, and occasionally for things like a bad charge roll.

Assuming you want to put a hole in a critical vehicle, here is some math to help your decision.

A missed Dark Lance will on average do 1 roll × 2/3 hit × 2/3 wound (assuming < T8) × 3.5 damage = 1.56 wounds
A failed Dark Lance wound will do 1 roll × 2/3 wound × 3.5 damage = 2.33 wounds
A Dark Lance damage roll of 1 will on average give you 3.5 wounds - 1 wound = 2.50 wounds
A Dark Lance damage roll of 2 will on average give you 3.5 wounds - 2 wounds = 1.50 wounds
A failed Heat Lance wound will do 1 roll × 1/3 wound (assuming > T6) × 4.15 damage = 1.38 wounds

Based on that a damage roll of 1 is the ideal option, but may not pop up each phase. A Dark Lance failing to wound is a fairly likely event and would be a good choice if you really need a tank to die.

Not a re roll but in maelstrom you can spend 2 CPs to re draw a card.
That can mean the difference between victory or defeat in a close game.

Painjunky wrote:

Not a re roll but in maelstrom you can spend 2 CPs to re draw a card.
That can mean the difference between victory or defeat in a close game.

Very good point!

I also like it for saves against those high damage weapons (if it means shooting worse next round/ dying)

I always blow a CP on seizing the initiative. Letting loose with all the darklight in my list before my opponent can do anything is too good an advantage to lose if I can help it.

Actually I've never really thought about it before but can you spend 2 CP to automatically seize?

|Meavar wrote:

I also like it for saves against those high damage weapons (if it means shooting worse next round/ dying)

In fact, you have to save each one of the wound received. Not just 1 save for all the wounds.

Huh? Not really. You first roll saves, then multiply by damage of the weapon.

Strange. I'm pretty sure I read it on an official faq, alongside the plasma weapon getting hot on a 1 or 2 against a venom.... But I can't find it anywhere, now.

@kantalla - thanks those numbers are interesting. Cool to see that rerolling wounding vs a t7 or below is almost equivalent to rerolling damage. That gives a great extra dimension to how to us these effectively.

Dumpeal- your thinking of fnp rolls like our 6+

Toffeehammer - only very specific rolls can be autoed ( unless you are a hemlock... !)

Personally I always use my re-rolls for either my Reaper's shots if he only gets a 1, or for the damage characteristic after I wound.

But also for D3's on objectives, trying to steal the initiative (if available), and also the Void raven's void-mine doing mortal wounds on a 3+ (kind of a waste, but it is in the movement phase, so why not?)

Kantalla wrote:

Mostly I have found them useful for damaging high wound targets, and occasionally for things like a bad charge roll.

Assuming you want to put a hole in a critical vehicle, here is some math to help your decision.

A missed Dark Lance will on average do 1 roll × 2/3 hit × 2/3 wound (assuming < T8) × 3.5 damage = 1.56 wounds
A failed Dark Lance wound will do 1 roll × 2/3 wound × 3.5 damage = 2.33 wounds
A Dark Lance damage roll of 1 will on average give you 3.5 wounds - 1 wound = 2.50 wounds
A Dark Lance damage roll of 2 will on average give you 3.5 wounds - 2 wounds = 1.50 wounds
A failed Heat Lance wound will do 1 roll × 1/3 wound (assuming > T6) × 4.15 damage = 1.38 wounds

Based on that a damage roll of 1 is the ideal option, but may not pop up each phase. A Dark Lance failing to wound is a fairly likely event and would be a good choice if you really need a tank to die.

Now, the question is:
Do you save the re-roll for the Dark Lance damage roll or do you use it to re-roll failed wounds?

You only get 1 per phase.

It comes
Down to if you need that do to wound, or you have more to come.
It is better, marginally, to wait but the. You have weigh that against the utility of that dark lance being used for something else.

Because of the opportunity cost it may be better to use it for the wound roll!

So question, when do you guys use your rolls? Early game to get the cascading bonus of its efffect, or late to alter a turning point of the game

When it matters.
I usually try to use it when it would actually have an impact, so maybe the first turn to get that first blood, or get a vehicle to slow down/die. Then most of my rerolls happen around turn 3 when massed charges happen and I need to make sure some unlucky dice rolls do not end up in dead drow. I feel this is often the moment that makes of breaks the game. Of course last game I had so many (he had one and a half as much points as me) so I could use them whenever, and I realised to late that I had been to stingy with them and had a few left over at the end.

You can also reroll the roll-off for the Wyches special rule.
Winning that roll-off has a huge impact on your opponent's turn.