Jan - I'm fairly certain that you and I would be in 99% complete
agreement about how to process a particular source of information. I
agree wholly with Thomas Jones and delight in Judy Russell's "It
depends..." The important thing is the analysis and I do worry that we
obsess over concepts like primary & secondary to the detriment of that
analysis - an obsession that is not helped by the different
definitions that we use. You might call the 90y old mother a primary
source and I might not but we would both be thinking of the memory
issue, etc. Or, to take another example, someone in the US might refer
to a politician's memoirs as primary (they were there) while I might
call them secondary (they have a stake in them) but both of us should
be thinking about whether there is any reputational advantage to the
politician being economical with the truth.

Adrian