The census, taken every ten years, provides a snapshot of a day in the life of your ancestors. It is enormously helpful in finding out where they lived, with whom, and what they did for a living. Working through the censuses you can track an ancestor's journey through life: discover when they changed address, started a new job, or got married. Your ancestors’ households will often reveal the names of their siblings, whose details would be difficult to trace using the birth indexes alone.
The earliest censuses only recorded statistical details for England, wales & Scotland. The first to record the details of individuals was the 1841 census, although it contains less information than the censuses that followed. The 1841 census enumerators were instructed to round down a person’s age to the nearest multiple of five. A person aged 69, for example, was enumerated as 65.
Due to the personal nature of census information, a 100-year secrecy rule is in place. This means the most recent census available is the 1911 census, which was released early (with some information redacted) after an appeal lodged under the Freedom of Information Act.
On findmypast, you can view the previously hidden information in the 'infirmity' column of the 1911 census for England, Wales & Scotland. If your ancestors filled in this column, you'll be able to see information about your family's health in 1911.
As the census returns relate to a single day, it's possible that your ancestor was not where you would expect them to be. If they were visiting someone when the enumerator called they will appear on the list for the house they had visited.
Errors are inevitable in any record-set, but particularly with census records, because illiteracy was quite common in the nineteenth and early twentieth centuries. Ages can also be wrongly recorded - people were sometimes liberal with the truth.
As a rule of thumb, less is more: the more information you enter for your search, the greater the potential for errors. So keep your search criteria simple at first and only add more information if you need to narrow down the results. Once you find an ancestor on the census you may find siblings that you didn’t know existed, and the discovery of these siblings will create more lines for you to investigate and add to your rapidly growing family tree.
Discovering the area where an ancestor lived may lead you to research the area's history; while finding an ancestor's occupation may mean you want to learn more about the job they did and consult any relevant occupational directories.