I used to clean holiday cottages, too. One time, I got there bang on the dot (10 am). It was my son's birthday and we were going to rent a boat and go fishing as soon as I was done. Normally, if I really hustle, I can get that cottage clean in a couple of hours.
Don't you know, that was the one time the clients were still there. I got there at 10 and they were not even starting to really pack. They were sort of faffing about. It was a very weird situation: they weren't on holiday but said they needed a place for a week while moving into a house in the area. They'd enrolled their children in the local school, but there was no house. They just went around looking for a place to rent. A friend of mine had some cottages and flats and talked to them and said they were weird.... the mother had asked if my friend could drive her children to school every day, as they didn't have a car. 
Anyway, there were three adults and two children in a two-bedroom cottage. They weren't the usual holiday family with a couple of suitcases: they'd decanted their entire life's belongings into the house for the week.
I told them that they were supposed to be gone by 10am and they were saying "Oh, just give us a bit of time to tidy up..." I said, "No, you don't need to tidy up. My job is to clean. You just need to get out of the house so that I can clean." I was polite, but I think my annoyance was clear. And, when I say "You don't need to tidy up" that wasn't quite true. The clients were expected to leave the place as they found it, and then I would sanitize it, so to speak, and change the bedding. Well, they left it in an awful state. Rubbish everywhere. Children's toys everywhere. Crayon on the walls and chewing gum on the furniture. Fridge full of food and bins overflowing with trash. They even went into the storage cupboard under the stairs where the cleaning supplies are kept in a box, rummaged through the box, and took stuff. Many dishes and glasses were broken.
My son's birthday outing was spoiled and the cottage owner had to arrange other accommodation for the guests that were due to arrive that afternoon. He had to come up from England to redecorate because of the state of the walls.
He kept their entire deposit and paid me most of it for my cleaning. They left a scathing review on Trip Adviser about how awful it was, how cheap the dishes were (they broke so easily!) and remarked on the "nasty cleaner who was rude about us wanting to take our time in the morning."