Probate records can be an excellent source of information for family historians, sometimes providing information over several generations. They can confirm family relationships over a large distance, from different counties or even countries, and provide the proofs required that a particular family is the correct one being traced.
However, they do not normally provide exact dates of birth, either of the testator or any beneficiaries mentioned. Children and young adults were usually described as simply being under the age of twenty one, and sometimes in age order, such as "my eldest son", "my second son" etc.
But one will examined recently by our research team was unusual in that the testator, William Innes, included exact details which he wished to include on a memorial table to be put up in his memory, and that of his wife. Perhaps he did not trust his executors to get the details right, and he included his date and place of birth, as well as marriage, within the will itself.
William Innes' date of birth is given at the beginning of the fourth line, and his marriage date in the middle of the fifth line.
It just goes to show that whilst generalities can be made within genealogy, you never know what the next document will show!