Generally survived for a month or two. Tatterdemalions were one of the few types of Faerie Creatures that had survived the unbalancing of magic by the Demons and the rise of the dark years of the Void.
They were born fully grown, did not age after that and lived only a short time. They took on aspects of the children they were formed from while never achieving solid form. Magic shaped and bound them and when that magic could no longer hold the memories and dreams simply scattered into the wind and the Tatterdemalion was gone.