If a birthday party is at a friend's house and they also have multiple kids, I'll usually ask if it's ok if we bring our other kid. So far it hasn't been a problem - and when I get to the party, there are a number of other sibling sets.

If a party is at a venue with a planned activity, then we'll just bring the one invited guest. We recently went to a party at a rock-climbing gym, and wouldn't think of bringing more than the one kid to something like that.

We had our son's birthday at a venue, but there was no big activity and we made it clear that people could bring their siblings. A lot of people did!

When do you bring just one kid to a birthday party, versus more?