My first novel come out at 85,000 words, and received the best reception from agents but at some point I stopped pursuit of publication (40 rejections) because I thought the plot had holes you could shoot a cannon thru. Second novel, The Shadow Warriors, topped at 140,000 words which I trimmed to something like 120,000. It's 400 + pages, big type, and does not seem to be a lengthy read. Promiscuous Mode also hit 120,000 and it trimmed it down to 114,000, and it, too, seems all right with all the subplots and twists. World of Mirrors also hit 120,000 words. What is it about 120,000 and me? I trimmed it down to 99,000 by changing the character and getting rid of the back story. It's now a good length for what it is. Festival Madness just hit 75,000 and granted, I am on the way to identifying the murderer and creating the exciting climax but I will be surprised it it, too, doesn't hit 100,000.
There are two kinds of mysteries: genre mysteries and mainstream mysteries. Apparently the difference is that a genre mystery is 75,000 - 85,000 words and is strictly a mystery. No or few subplots, not much description, no deep character depictions. Solve the crime and get on with it. These mysteries can be a good read and have devoted fans. I recall that I could start an Agatha Christie mystery at 9:00 and close the book at 11:00. A quick good read.
Mainstream mysteries are mysteries and then some. Subplots, a conflicted character, stuff going on in the character's life that churns through the words. These books are cross-over books in that readers who don't normally read straight genre mysteries may pick one up and read it. Of course, genre readers will, too, so in theory the book has a wider appeal. I know nothing about what really drives the sales of mysteries. Obviously.
I am a mainstream mystery author. But ye gods all those words add up.
When Festival Madness hit 70,000 words, I began to have trouble keeping track of all the little details. Had to go back and reread recent scenes. Apparently I can keep 70,000 words in my head and not a lot more. So I have to keep re-reading as I progress. Not a bad thing, just an annoyance. How many times did I mention the Quincy software house? Too many? Just right? Is it becoming a drag? Signally too heavily? Arrrrgh!
On Miss Snark I read about a 296,000 word fantasy. Jeeminy Criminey that's a lot of words. Hate to keep those straight. Thriller may chew up a huge word count. I have clocked a few at 200,000+ . My feelings about this. A book requires the words a book requires. A conscientious author will pare as much as possible and a little of possible and that's how many words are left. In the case of Festival Madness, I hope it comes out around 90,000. Seems like a goodly number. We get to see the man burn, the temple burn, learn about Jean Claude's love life and solve the crime.
Word Count. Numbers people like me love to keep track. There are some in my writer's group who don't have a clue as to how to figure it out. Use the PC as a typewriter and filing cabinet. Takes all kinds of writers. And readers. Hooray for that!