For my boy's birthday parties I invite their whole class as well as my girlfriends and their kids. I never have any idea who RSVPs or not.

I just buy a whackload of junk food and feed them all party pies and sausage rolls, ****tail franks, chips, cheezels, chocolate and lollies. And then cake. And to drink, they have red or green cordial.

Our parties start at 11.30 and finish at 1pm. They spend an hour eaten and mucking around. Cake is at 12.30.

The adults, who are welcome to stay, go through 3-4 bottles of French champagne, pate, cheese, smoked salmon and chicken.

After cake we play ball games. Culminating in poison ball.

Because it's hilarious for ****ed adults to throw balls at kids they don't like.

Sorry, back to topic. I'd RSVP straight away. I have received a number of calls from parents looking for RSVPs when XH was supposed to do it. He doesn't. So I chase him for it.

I guess it's pretty individual.