Does regeneration "stack"?

[gglibertine]

So I've got an artifact that gives me regeneration, and I'm already wearing an amulet of regeneration. Will wearing both make me regenerate faster, or am I just wasting a slot now?

[zaimoni]

Regeneration does not stack in V. I do find it useful enough to expend home slots on, however (store the amulet if the artifact makes sense to use).

[Moving Pictures]

But does regen from a device stack with half-troll natural regen?

[Derakon]

No. The only stacking effects in the game either explicitly have numbers attached to them (like +STR, +speed, etc.), or are permanent + temporary resistances. Otherwise effects are binary: you have them or you don't.

[Pete Mack]

Not in V, though yes, in certain variants. Of course, this means more hunger, too.

[Thraalbee]

How does impair hit recovery stack with regen? E.g. =openWounds & =regen. And then after adding "regen on top of that

[Nick]

How does impair hit recovery stack with regen? E.g. =openWounds & =regen. And then after adding "regen on top of that

If you have one or more sources of regen, regeneration is doubled; if you have any one or more sources of impair hit recovery, regeneration is halved. So both your cases above give standard regeneration.