Our daughter ( now 17) started sleepovers in K. Of course we knew the families, etc.
As the years went on, most of her sleepovers started occurring at our house. Why? Because I guess, she's an only child and it was less work for parents with other children. That was ok... In reality, it was a blessing because she has the entire 2500SF upstairs to herself, it's a perfect spot for sleepovers and I know where they are and what they are doing. Other parents also know that I will let them have fun and enjoy themselves but I also expect them to respect my property and follow rules or be taken home.
Some parents are very rigid when it comes to sleepovers and prefer to raise their children in bubbles as long as they can because they value their own sleep vs allowing children being children. Children need to experience outings, explore and learn to appreciate what they have.
My view.... I'll have plenty of time to sleep when my daughter heads out of the house to college and on her own. I will never have a "do over" on being selfless and allowing her to enjoy her childhood with treasured sleepovers and involvement with her friends.
Even today at 17, at least 1 of our weekend nights has 4-6 teens here cooking, playing pool, wii, etc in a safe environment.
Bottom line, you do what you feel is right for your family.