A handy tip for all those new to family history research is always be alert to the fact an ancestor could appear on a census listing more than once. If your ancestor moved around a bit, or lived an unconventional lifestyle there is always the chance they may have ended up listed in the census more than once. A case in point is that of daring early aviator and showman, Samuel Franklin Cody. American born but living and working in Britain around the turn of the 20th Century. Before becoming employed by The British Army, he worked with his family on a wild west show and regularly toured around Britain and Europe. Samuel Cody then became interested in aviation and subsequently became one of the leading pioneers of British aviation. However, around 1901, the Cody family, with their show and their lifestyle, inevitably meant moving about quite a bit which may explain his two entries in the 1901 census. Both entries are from the Cheshire census and it looks like the Cody family may have had two temporary places of accommodation as they took their show around the North West of England. Both Samuel (senior) and his son Samuel Frank Leslie Cody appear listed on the 1901 census records in the screenshot below from TheGenealogist.
This famous example shows what can occur so always look out for those duplicate records!