I'm glad to hear that the greater majority of your guests who are welcome to return. Just how often does that happen? I'm kind of into seeing what kind of deals I can get and staying at different places, but as I've said, I've only done it twice now, and I'm never probably going to go to the same area so many times that I'll end up booking the same place again (even if it is available).
If I were ever going to own a property to rent out, it would be a vacation rental, and most likely through a service like Airbnb. Advertising it yourself can be some time and money, too, so there's always the trade off. I don't like the idea of long term renters (it seems to me that without regular checking in, all kinds of things could be happening, like what you described, only over longer periods of time).
I guess there's not really a way to keep track of the terrible to bad guests, though I would think hosts get to rate their guests, too, right? They're bound to be the same in more than one place if they've rented more than once.
Fairly often, I've had a couple people stay 8-10 times even, a few days at a time. I had someone stay last week, that I hadn't seen for over a year and a half too. But a bunch more that have stayed maybe a couple times.
After the initial first few weeks they show their true colours. People get to the settled in point. Some people are naturally bad to begin with, but even people that might be great for 2-3 weeks might just be putting on a show for you. haha. I cap it at 4 weeks, generally don't see longer than 1 to 2 weeks though.
Yup, I had a guest recently that turned up drunk and puked on my carpet, I gave him a bad review and he was literally begging me for forgiveness in the chat after my review came out. He wanted me to change the review, but once both sides are posted that is it, they can't be edited. No chance I would edit even if I could.