The thing is - we all know that "expenses" are allowed to grow to match or overtake income. Usually without corresponding savings/investment.
I can tell you that you WILL spend MORE in retirement than when you're working. You just don't have time to spend when you're working all day. Wait til ya got nothing to do all day - every day - and someone says "hey! Let's all go to X...." You're in!
You don't spend on the same stuff.... but you'll spend it on hobbies - trips - dinning/entertaining - and MEDICAL. Ya get older - insurance goes up - trips to the doc increase - meds you didn't use to need are now required etc.
The problem with retirement "lately" has been the utter lack of returns. If the returns get better -- your investments grow quicker (compounding) and when you retire -- getting 8% on a million is WAY better than getting a lousy 4%!!
The keys to this ---- by retirement have your expenses down to basics ---- and investing EARLY so it has time to compound.... One has to go UP and the other must go down. Or -- you live for 25 or 30 years wish'n' you'd have done a better job on something you had plenty of time to prepare for.
It used to be you inherited a little from your folks.... but I'm telling ya that about the only thing most will inherit any more is the debt from taking care of them in their final years. You/they will have blown thru the house - savings - and anything else not nailed down if they stroke - or get cancer - or require assisted living. I can tell you this via my own personal experience with my parents. 4 years of assisted care --- ya got nothing left. And these days people live longer but then they seem to need more care in the end.