For qualified 529 plan expenses for a student living at home, I realize I need to look at the school's COA for room and board and not exceed it. However, I have read hundreds of posts and am surprised I can't find some sort of formula or average for coming up with a reasonable estimate for these expenses. For example, if the student lives at home as part of a family of 4 and has expenses just like when they were a minor, with no separate receipts for groceries, internet, eating out, etc., isn't there some sort of "typical" estimate a person can use for these expenses, such as "an average student eats $x.xx per day (or consumes 1/4 of the total groceries)" + 1/4 of the internet, etc"? I'm not necessarily trying to find the max amount, I'm just trying to determine a fair amount that wouldn't trigger an audit and wouldn't require a pile of separate receipts for one person for a year.
