Spelling surnames correctly wasn't important like it is today and people would change a letter or complete spelling on a whim. Maybe it was with great thought for some but for others it may not have been. Either way it can be quite a task to track our ancestors down when no match is found for a person that should absolutely be there. Some times its best to try the first letter or the first two letters then the first three letters and so on. Try different spellings and other family members such as a sibling, spouse, and even a child.
Birth dates and ages are another way to make someone pull out their hair. So you have the right name and possibly some of the family members match even though the names are wrong and maybe some of the birth dates on the children are close. Before you quickly decide that this can't possibly be the person you were searching for I have great news to tell you. I have found through my own research that a great percentage of people gave incorrect birth years, dates, and ages on census records. I can't blame them really. If someone comes to their door and asks them how old they are without needing to show them any proof of their age why not be 5-10 years younger or more? So when conducting your research don't count on age as 100% if the person is in the right place at the right time with matching family members and the age is within 10 years plus or minus then you've got some more researching to do to either count the person in or out of your tree.
Nicknames oh how I love them except in the census. I was researching a family with an unusual family name so I thought it should be fairly easy to find all of their census records. Yes, it would have been easy except for the very strange names given to all the family members except the head of house hold. It wasn't even a middle name. Just cute made up words that they called all the children. That turned into a very long research case but I finally was able to figure out what their names really were.
Middle names can be just as complex when researching Census Records. Especially when you only know a first and last name. That is when you will need to really be a detective and investigate them forwards and backwards to determine if the name you have found could possibly be a middle name of the same person.
When researching let the documents point you in the direction and always keep an open mind. Sometimes its easier to think that a person isn't in your family then to prove they are. An open mind and following the documents will help you determine what the answer truly is.