I have a number of people on my family tree that did/do use a different first name than the one they were given at birth. In some cases, they have used their middle name as their first name, in others they have seemingly just picked a name that they liked and used that instead.
This obviously causes havoc in research, with birth and marriage records not matching the name others in the family remember them as.
Is there any consistent/typical reason for a change of name, other than just personal preference? Any research been done into this area that you're aware of?