I'm not Elizabeth, but had to chime in here. Once our girls were old enough for parties we allowed them to invite as many kids as they had years under their belts. So, the parties got bigger as they got older, but they were certainly more manageable!
There was one exception to the rule and it is kind of a touching story. For Kristin's 6th birthday she wanted to have her party at McDonald's.

So we started planning an August party for Kristin plus her 6 friends . We took my parents and my siblings to the beach with us that June and were talking about the birthday party and my parents both thought it sounded like fun and planned to be there, as they had been for every single birthday my children ever had. No matter where we lived they also came to visit us on my birthdays too.
But when my birthday rolled around in July my father wasn't feeling up to the trip to Virginia so we went to PA instead. He took me aside the day we left to come home and said, "Missy, I don't think your mother and I will be able to make the trip to Virginia next month for Monkeyshine's birthday. So I want you to invite everyone from her Kindergarten class." He handed me a blank check.
Every single child from Kristin's Kindergarten class came to that party. The place was packed. And those "kids" still talk about it now! And Kristin remembers that her Grandpa made sure she had a birthday to remember even though he wasn't there. That trip to visit them that July is one of her last memories of him.