On Tue, Feb 4, 2020, 09:40 Nina Jenkins <... ideally confirm each piece of evidence from 3 sources before trusting it totally.
Even there, we have to be sensible about it - it does say, "ideally" after all.
I'd hope that no-one would regard 3 Ancestry trees as satisfying the required level of trust - especially not if they all copied the same original.
And once you're well back before civil registration and censuses, there may be no other evidence of birth date other than the baptism - no age on marriage or burial or anything else - so many people will have only one source for their birth date.
The Genealogical Proof Standard is not the answer to everything but it has good advice here when it requires "a reasonably exhaustive search" (I think that's the phrase). Get what you can and when you've exhausted what it is reasonable to look for, don't worry about it any more.