If you've ever read any of the myriad of books on writing, one of the biggest rules seems to be 'write what you know'.
I think you should write what makes your imagination fly.
I don't want to place my stories in my actual location - it doesn't fire my imagination. It's home. It's familiar. Nor do I want to write about situations I know or have experienced. Honestly, how many stories could you write about taking care of children and trying to keep a house somewhat clean? Perhaps you could write hundreds - it leaves me dry.
If I took this caveat to heart, I could write about the theatre - and I must admit I've given it some thought. Non-theatre people (known as civilians) are often fascinated with what goes on behind the curtain, or in the rehearsal hall. The problem is the reality of that world isn't as glamourous as people think. It isn't a world filled with feuding - most of the time. Most actors, offstage, are fairly regular people. So are directors. No one calls each other 'darling' or slinks around while flicking their cigarette-holders. It's work. Learn your lines. Do the show. Worry about getting another job.
I don't live in England - nor do I live in the 1930s or 40s. But this is the time and place that makes my imagination fly. It's impossible for me to learn too much about it - my bookcases are filled with books and I watch every documentary, movie or television series I can about the period. I find it endlessly fascinating.
It's not what I know from living it. But, I guess, in a way, I am writing what I know.
How about you? Do you write what you know?