"My experience is that most of my research tends to be done to make sure I haven't accidentally said something that *isn't* possible (i.e. trying to establish what a pocket-book actually is and what it looks like, in order to confirm the plausibility of a single line of period dialogue invented off the top of my head) rather than in order actively to convey the information in question. Which probably helps ;-)"

Oh yes, in spades. Nothing drops me out of a book like a glaring factual error. I remember one historical romance where the protagonist kept a pair of lobsters in a tank in an inland Scottish castle with no electricity...

And another novel where the geology was screwed - a series of underground caves in granite rock. And another novel that lost me by having several different types of spring bulb all flowering at the same time.