Health regen example

function Item.setHealthRegen(self, amount, ticks)
    self:setAbility(ITEM_ABILITY_HEALTHGAIN, amount)
    self:setAbility(ITEM_ABILITY_HEALTHTICKS, ticks)
    self:setAbility(ITEM_ABILITY_REGENERATION, 1)
end

function Item.removeHealthRegen(self)
    self:removeAbility(ITEM_ABILITY_HEALTHGAIN)
    self:removeAbility(ITEM_ABILITY_HEALTHTICKS)
    self:removeAbility(ITEM_ABILITY_REGENERATION)
end

local item = player:getSlotItem(CONST_SLOT_RING)
item:setHealthRegen(50, 1000) -- regen 50 health every second

-- later
item:removeHealthRegen() -- regen will no longer work