It is not just the spelling that flummoxes me is that gut reaction of whether or not they are the same person you are searching for. When I find a person that practically matches to a tee who i am searching problem is the uncertainty of whether or not it is the same person or a different person with the same information. two different people could have the same first and last name, same birth and death day, same spouse, same parents, but not be related to each other at all. With just one bit of variation difference in their information could tell them apart.
example: 1.John Smith born 12/12/1890 died 3/6/1970 parents Mike Smith and Mary Tomlin.
there is a another 2.John Smith born 12/12/1890 died 3/6/1970 parents Mike Smith and Mary Tomlin. Say John Smith (1) name is spelled Jonathan Smith while John Smith (2) name is spelled Jonathan Smyth. John Smith 1 and John Smith 2 could be viewed as either the same or different person. How would you know? John Smith 1 and John Smith 2's parents could have different spellings of their first and last same, different birth and death days, different parents. Or their parents could have the same information with some possibly minute differences,
what I am saying is u could be adding John Smith 1 to your family tree only to find out John Smith 2 could have also been the right person to add to your tree.
On records I have seen the John Smith 1 and John Smith 2 situation a lot. Sometimes with John Smith 1 and John Smith 2 situation i get the feeling this may not be who i am looking for. I have trimmed the family to find out i regret it later. I add people i feel fine. I find out more information that leads to the possibility of a person not being related. Even though on a record it said they were. On another record it says they are not. John Smith 1 and/or John Smith 2 grrrrr. It is impossible for me to explain in words how frustrating Genealogy is. I take like 5 steps forward only to find out I went the wrong way some where. I am continually backtracking and correcting myself.