If you’re using population registers, keep in mind that these registers were often copied from older registers and may contain copy errors. The birth dates mentioned in them were often not written close to the time of birth, and the informants may have made mistakes.
If you find a birth date in a population register, always verify that information using other records. More reliable sources for birth dates are birth records or baptismal records that were created shortly after the birth, with eye witnesses as informants.
See the article about the parents of Gerardus van den Heuvel for an example of an error in a population register and how that was resolved.