Really depends on what the gentleman wants and if the provider is willing. I've done many overnights, but mostly with regulars who desired a combo of carnality and companionship. Usually started with dinner and a show/concert/day at the RenFest/some festivity, then more fun in private, restorative sleep, perhaps a sexy snack in the wee hours, ZZZZZ, then a bangin' breakfast or wake-up blow.
I've also cooked for fellows, had a few take over the kitchen from me, or we ordered food in and munched nekkid in bed watching a DVD, then relished each other the rest of the night, with intervals of pillow communion.
Some gents want a dusk-to-dawn marathon of non-stop gymnastic gyrations, but if so, I advise them to call someone younger and more energetic, and make it absolutely plain what's expected. Gives the provider a chance to nap beforehand, plus not schedule anybody else immediately the next day so they can grab some rest.
Just for trust and safety issues, it is indeed best to only do overnights with well-established ladies/gents you are already at least somewhat familiar with. However, that isn't a guarantee. A couple of years back I had an out-of-town businessman who I had seen several times before walk off after an overnight and "forget" to leave my donation, and since I had spend pleasant multi-hours with him previously and never had a problem, no, I stupidly didn't collect up front. He "forgot" to ever send it via Paypal, and I never heard from him again.
Eight to 12 hours is a lot of time to spend with another person you don't know well. If you're considering an overnight, OP, why don't you do a dinner date "test drive" first and see how 4 or 5 hours go?