I would rather have 3 parties, esp. if I could afford to hire help.
Because a party of 30 is fun with lots of opportunities for interaction, but a party of 120 is completely impersonal. If the place is big enough, 40 would be nice but (to me) beginning to veer to the impersonal.
And I love the grab-bag of names each year, so that for guests, some of the people are people you've partied with in previous years, and others are new-ish.
With repeated nights, the food can be essentially the same, just more of it. The place is all spiffed up once.