There are several good reasons to merge pages:
/>'''Duplicate''': There are two or more pages on exactly the same subject, with the same scope.
/>'''Overlap''': There are two or more pages on related subjects that have a large overlap. [[Wikipedia:Wikipedia is not a dictionary|Wikipedia is not a dictionary]]; there does not need to be a separate entry for every concept. For example, "flammable" and "non-flammable" can both be explained in an article on [[flammability]].
/>'''Text''': If a page is very short and is unlikely to be expanded within a reasonable amount of time, it often makes sense to merge it with a page on a broader topic. For example, parents or children of a celebrity who are otherwise unremarkable are generally covered in a section of the article on the celebrity (and can be merged there).
/>'''Context''': If a short article requires the background material or context from a broader article in order for readers to understand it. For example, minor characters from works of fiction are generally covered in a "List of characters in <work>" article (and can be merged there); see also [[Wikipedia:Notability (fiction)]].
Merging should be avoided if: