In pre-industrial societies, most people lived in multi-family dwellings for most of their lives. A child lived with their parents from birth until marriage, and then generally moved in with the parents of the man (patrilocal) or the woman (matrilocal), so that the grandparents could help raise the young children and so the middle generation could care for their aging parents. This type of arrangement also saved some of the effort and materials used for construction and, in colder climates, heating. If people had to move to a new place or were wealthy enough, they could build or buy a home for their own family, but this was not the norm.