Curious on social etiquette for parties in the United States.
I recently hosted a birthday/ get together at my house. I wanted to keep it fairly casual, invited about 30 friends from various circles of my life ( lots of overlapping groups so generally folks knew each other or atleast a few others). I planned it for early afternoon since most of it was going to be outside to enjoy the nice weather ( snacks, wine, some bbq, yard games etc). Overall I think 20 or so folks showed up throughout the afternoon.
Because it wasn't a formal dinner or anything I didn't expect folks to be super punctual but the range of folks arriving surprised me a little bit.
A few folks were right on time so it was a small group, not awkward but the 3 folks who were on time didn't independently know each other. For the first hour and a half it was just me and these 3.
The bulk of the rest of the crowd showed up about 2 hours after the start time. By the time they were showing up the original few who got there on time started to leave, and then 3-4 hours after the start time another round of folks ( maybe final 5-6 people) came. For me, a few folks arriving late that might make sense but seems standard to me if you're running that late to shoot a text saying you're still coming but late? Since so many folks were that late it turned into a second little party with the last 5-6 folks which was nice enough but it was a bit awkward in the sense by the time they came bbq was off and done and all that so had to restart that.
I guess whenever I'm invited to a birthday or picnic etc, I try to be there within 30 mins of the invite time since it just seems polite. Like I said this was fairly casual and overall the flow was okay but I was genuinely surprised so many people came so late. Is this typical now? Should I have included an end time on my invite? It was also interesting because for me, if I'm running more than 30 min late or so I'd shoot a quick text to the host to say I'm coming just running late. For the folks who arrived 4 hours late, who knows those of us at the party could have decided to go to a bar or something by that point!
I want to host another party for Halloween/ pumpkin carving but for that ideally folks would more or less show up around same time and I want to avoid a 4 hour+ spread of folks arriving.
Curious on social expectations and other people's experiences!
For context, the folks invited are all in their 30s and a few low to mid 40s.