Nodes, Caerns and Glens House Rule
Because Mage and Werewolf have different points of view on this matter, this is how we will be running caerns and glens in relation to nodes.
Nodes are locations where free quintessence gathers. If enough quintessence gathers over time, tass forms. Nodes make spell-casting easier and lower the Gauntlet at their location. Most nodes are only destroyed when they are physically destroyed or the conditions that caused them to arise are destroyed. Most nodes are not destroyed when all their free quintessence and tass is taken. It simply takes them time to regenerate.
A caern is a node created by a ritual between the changing breeds and a powerful spirit; it helps changing breeds reclaim gnosis and may produce other effects for those who can fulfill the requirements of the spirits that created the caerns. Like nodes, they make spell-casting easier and lower the Gauntlet at their location. However, if a caern's supply of free quintessence and gnosis (a form of tass) is emptied, the spiritual link created by the ritual is disrupted and the caern is destroyed. If the conditions which allowed the ritual to be performed still exist after this takes place, the caern can be recreated.
A glen is a pristine natural place where gnosis forms. It does not gather free quintessence; the gnosis produced there is a function of direct interaction between the location and the changing breed. However, glens have a special bonus for mages; they always count as being resonant for the Prime 4 spell, Wellspring. The danger there is that if they cause a paradox backlash, there is a possibility that they will destroy the glen's ability to generate gnosis.