Write what you know. The famous advice. And the older you get the more you know, or at least remember. Or maybe not?
I was rather indignant to discover that some of the undergraduate courses offered by my university's history department were about events I'd lived through. Huh! I was more amused to see a recent magazine article referring to a collection of vintage cookery books - some of which appeared to be ones printed by M&S in the late 1970s. I think they sold for £1. I have a large collection and yes, I still use them.
Thing like those cookery books can be a useful if unconventional research tool. I also find articles and magazines celebrating anniversaries can be be useful for an overview. The current ASDA magazine (no, they haven't paid me for the promo) is celebrating 50 years of the store and there are all sorts of reminders of food and fashion. I think that one will be going in the odds and ends of research drawer when I've read it. And yes, I remembered quite a lot of those too.
This post is making me feel very old.
But - there's a danger in all this. If you need to know something you research it. Easy. But what about the things you think you already know?
I've talked about this with other writers. There doesn't seem to be a solution, except more research. Of everything. Where do you draw the line? And of course there's also the matter of reliability of memory. That way madness lies and I'm scaring myself just thinking about it.
I don't have an answer. The best an author can do is their best.