That's definitely a tricky one from my personal experience. Since I had many guests visiting throughout the year, I needed to establish what was negotiable and what was not. For me and my young family, sleep time/quiet time in the evening became a non-negotiable. As an introvert (and an exhausted mother of two), I needed to wind down after dinner, have time alone, and decompress. So, in advance of their visit, I'd tell the company that 8 p.m. was the hour that the kids went to bed and our entire household shut down. While being assertive like this didn't come easily to me, it was necessary because some folks were watching television in our family room (right outside our bedroom) until the wee hours of the night, causing me to lose sleep, grow frustrated, and get downright grouchy (not a good combination when you're entertaining).
Even though I put a TV and reading materials in the guest room, some people just didn't get the hint. But enforcing the 8 p.m. rule really worked. I'd take the kids off to bed, turn out the lights, say goodnight to our guests, and ask them if they needed an extra blanket or pillow. I'd ask them to keep the volume down on the TV in the guest room.
Being assertive, spelling out the rules, and having open communication is key for a successful visit. While we certainly want our guests to feel relaxed and comfortable, we also need them to respect our schedules. They may be on vacation, but we're still working and keeping a routine.