Let's take a close look at how HeroClix probability works.

First for the uninitiated -- Probability Control is a power that lets you reroll your dice once. Of course, if you have two uses of Probability Control, you'll be able to reroll your dice twice.

First, we'll take a look at probability with just 1d6. This is a great chart to use if you're rolling a single die with something like Support, Regeneration, or Blades/Claws/Fangs. Remember that you can only use Probability Control on your rolls during your turn, so you typically can not reroll Super Senses or Impervious. (Note that some numbers are rounded)

Edit: [2] has been clarified to show unrounded values.

WITH BLADES / CLAWS / FANGS
For those using Blades/Claws/Fangs, a common question is: "Should I use the printed damage, or roll for BCF?" It depends on your odds, and if you like to gamble. Statistically, if your base damage is [3], then you should use BCF since odds are good (67%) that it will result it will result in 3 or higher.

With a single use of Probability Control, statistically you should roll BCF if your base damage is 5 since you have a 56% chance of rolling [5] or higher. (Personally though, in this situation, I would only roll of my base damage was 4 or lower).

Right: Discounted HeroClix Singles

And even with 2 Probability Controls, rolling a [5] or higher has a whopping 71% chance.

Honestly though, if you're already doing [5] base damage, then BCF isn't even worth it it unless you're really trying to spite your opponent. And even more honestly, I've rolled a [1] more times than I care to admit (note there is a 17% chance to roll a specific number without Probability Control).

So do you use BCF or not? Statistics don't lie, but honestly it comes down to how lucky you feel. As a rule of thumb, always roll for BCF if your base damage is [2] since there's only a 17% chance it will show up as a [1].