Question about artifacts

[HellWeasel]

I apologize if this has been gone over already but my SearchFu is unable to locate anything that will answer my question.

Several Artifacts grant skills that are activated upon certain conditions, low health, taking damage, etc. In my dabbling with artifacts it seems inconsistent on when they work. Can anyone explain to me how exactly it determines when that skill is going to be used?

Some of the artifacts have some pretty awesome abilities but if they aren't going to activate I wonder if I'm better off taking a different artifact.

Thanks

[Siberys]

I guess it's just a percentage chance of being activated. I have no clue as to what that percentage is, but I'd say it'd activate anywhere from 1 to 10% of the time considering the magnitude of many of the abilities.