Of all the documents in Elam Blain's Revolutionary War pension file, only two give his age on a specific date in time. These statements of age are made on affidavits early in Blain's application for a pension based upon his service in the Fourth Continental Regiment of Light Dragoons. He was living in Ohio at the time of his application. The ages and dates they were given are.
Aged 60 on 1 May 1818.
This means that Elam was born between 2 May 1757 and 1 May 1758.
Aged 61 on 10 August 1820.
This means that Elam was born between 11 August 1758 and 10 August 1759.
The only problem is that these age ranges do not overlap meaning they are inconsistent. One or both of these ages are incorrect. While the ages do not agree with other they are not significantly different.
What am I to do?
The first thing is to consider how reliable I perceive the ages to be. I should look at the pension act under which Elam applied and see if there was any age requirement that was a part of it. That could impact the perceived accuracy of his age or it could have impacted when he applied.
Elam's pension file indicates that he lived through the 1840s. Checking for him in the 1840 census and before is advised. Those censuses do not provide precise ages, but would be helpful in determining the reasonableness of these ages. There is always the possibility that an age is "fudged" for a pension. Census ages can be off, but for slightly different reasons.
Once we have the census age ranges for Elam, we can refine our estimate of his year of birth.