So I'm sure I am going to be very unusual here. What we do though is we started allowance at age 3. A dollar per year old. They have to donate one, save one, and can do whatever with the extras. So the save envelopes will have quite a bit in them by the time we go back. Our younger children at the time we go will be a newish 3 and a 1.5 year old so we will get one thing for the 1.5 year old and 2 for the newish 3 since she hasn't had the time to save. Since our last big travel was cancelled for COVID, the older 2 will have a triple digit value in their save envelopes so realistically could have a lot to spend. At their ages big trips like this are as about as big as they can fathom saving for so if they empty those envelopes so be it. I do intend for them to list what they want to buy and the price until halfway through the trip so they have a chance to see if they really want an item after they see everything else.
Again though, I know we do money very different then most people. I had a father who was a CPA and taught me finances in a very practical way like this and I felt a benefit so I'm carrying on with my kids.