CENSUS INFORMATION BY YEAR OF ENUMERATION
Each year, the information captured on the census differentiated. For example, in 1850 and 1860, the slaves were listed in a separate census but for 1790-1840 they were not. And in 1900, the birth year was captured but it was not for any other census year. This type of information can help you confirm the age of your relative using the date the census was taken. Did they already have a birthday, or was it later in that year? Using the census and the information captured on the form helps to confirm your theories; but keep in mind, the information on one census may not be captured on another one.
Resource Links: National Archives Search Census Records