The one thing you can count on is the date and place of birth of the person. Filed first in a county or town, then a state copy filed. Deceased persons transported across state lines usually require a burial permit. Filed at a county or state health department, data about the deceased, including a date and place of birth may be included. Found at a city or county office.
Modern records have great genealogical information.
Earlier ones may only give name and residence. Many churches maintain christening records, which in most cases are naming ceremonies. Typically, a child's date of birth, name of parents, and names of godparents are included in the written record. Churches maintain lists of members. Some churches even publish photo albums showing all members for a year, and many of these lists include vital information.