Some of my friends on the other hand . . .
Okay, enough willful misunderstanding of the question. Honestly? When it comes to the Dandy Gilver mysteries, very little. These are my hommage to the golden age and I don't put anything in them that you wouldn't have been found in Dorothy L Sayers, Margery Allingham or Josephine Tey (although I'm not sure I ever have managed a tone as dark, bleak and just plain nasty as some of Allingham's - how these ever got the cozy title, I'll never know).
So, it's an extra constriction, to be sure, along with the requirement for an early murder, a late solution, and some red herrings, but if we minded constriction we would hardly be writing in this genre, would we? The compensation for me in the Dandy stories is that no one has a mobile phone, there is no forensics and I never have to write one of those desk-bound google scenes. When Dandy Gilver and her sidekick Alec Osborne dig for background they do it in dusty church vestries or the mahogany-lined offices of shipping agents or what have you, with scope for all manner of Dickensian walk-ons.
But now I've started writing modern stand-alone suspense too. In the first one, As She Left It the story didn't throw up much in the way of either graphic sex or explicit violence. It was a relief not to have to keep checking the vocabulary in the Shorter Oxford for anachronisms, mind you, and I may have gone slightly F-tastic with the curses just because, for once, there was nothing stopping me.
In the new one (working title The Day She Died) the story does involve sex and violence and I've followed the characters into the bedroom and out again as well as watching the bones shatter and the blood drip from quite close-up too. It's still being edited. Maybe some of the squelching (sexual and violent) will end up on the cutting room floor. If so, it'll be because, as Chris said yesterday, the story is better without it. We'll see.