Plenty of opinions follow...but one thing that's traditionally peeved me is to open a historical fiction book and find the characters all saying, "'tis" or "'twas." Is this verbiage there to alert me that I'm about to read something set in another time?

I submit that this MIGHT be lazy writing.

Let me explain. Let's say we're writing a medieval, set in England. They did not speak a language we'd understand today, without much study. After the Conquest, the upper classes spoke French, true, but as time passed it changed into something called "Anglo-French", which we probably wouldn't understand well even if we spoke modern French.

They used words that have gone out of usage. "An" for "if". "Eke" for "even." "Eyren" for "eggs." Do we include these words in our books, or use if, even, eggs? Why then would we go back to "'tis", which also is archaic usage? Because it communicates easily and still signals the era in which our story is set?

Possibly.

I set out, deliberately, to write SEASONS IN THE MIST without using either contraction. But I did, also purposefully, include certain ancient usages in contexts where I was sure it would communicate. I used "an" for example, in places where the modern reader would be very sure it means "if."

I'll wait for my readers' input next year, to tell me if my approach works. But I do think most historical fiction readers are smart enough to do without signal-words.