We have so far (and will this year) had a big do for DD's birthday - it's something we enjoy doing, so we do it. we have family and friends that travel several hours to be here for the day, so it generally starts at lunch (ish) time and finishes the next day when the last stragglers leave. its' something that we want to do, so we do it. it doesn't hurt anyone else so why not? Not sure what will happen when she's at school - at a guess, there will be more kids and more adults, so we'll have less food left over at the end....