If you work the whole thing out on 2% real return it's a lot easier.... We all assume that our outgoings need to stay level until we cark it, but that's just not the case. If you think you need 14G Oz to live yearly until 70, (if you work until 65 in aviation, check out how many years you will have left after you retire with an actuary, it's truly frightening), you are in the wrong job!
