Be sure to check all years, so you can be reasonably certain you're working with accurate information. One year the husband may have answered the questions, and ten years later, the wife got to do it if her husband wasn't in the immediate vicinity of the house. Ages and year of birth may vary considerably from census to census, plus the "Relationship" column may, in some years, have notations such as "adopted dtr.," "niece," "stepson," "grand-daughter," "mother-in-law " "father of head of household," etc.
Different census years asked for different things:
1850 and 1860: ask for the names of all members of the household and their relationship to the head of the household, plus the state or country of birth for each person .
1870: asks if their parents are foreign-born, etc.
1880: also asks for the state or county of birth of the parents of each person listed, even if the parents are deceased or living elsewhere. Asks if people are divorced.
1900: asks for the month and year born, the number of years married, number of children, number of children living, and year of arrival in U.S., etc.
1910: asks if a Union Veteran. There should be a check mark next to the answer to this question, because the space in this column is often used to indicate miscellaneous information. Asks number of times married.
1920: asks for year of arrival in U.S. and year of naturalization. Asks if divorced, etc.