I've created two monsters!

I love my kids' friends (most of them, anyway) and I think it's great that they like coming over to our  house. It's actually easier than me driving them somewhere else and they're good kids -- polite and helpful (again, for the most part!). I am starting to burnout on sleepovers, though. Every weekend, both of my kids have friends sleepover and it's rare that we have a night when our family hasn't temporarily grown by two extra kids. Part of me figures it's good that the kids are entertained (safely and cheaply!) but ...well, I don't know...am I craving more time with the kids myself? More quiet time in the house?

I can't quite figure out why it's concerning me, but thought I should check in with other parents: How often do you allow your kids to have sleepovers? My kids at 8 and 10. We've been having kids over for about six years now. Maybe I just need to suck it up but another 10 to 15 years might kill me.