Around 6, kids could be very excited by a sleepover party for just a few kids. By 10, kids may be out of the big party thing. The benefit of big parties now is you may actually train your kid not to want that. We did the huge invite the whole class style party every year for DCs. I thought it was the nice thing to do, to invite everyone, and that my kids liked it. They actually didn't like the big party scene, but I was so enthusiastic, they tried what I suggested. Starting about 8 and 10, they told me they'd rather not do anything, if the only other option was a big party. Since then, we have stayed small - a few kids to dinner and a movie, or a sports game, etc.