Edited to add. Just realised I worked this out based on 14.50 per work day, not 14. But it needs to be invested, not put in a savings account as you need the higher interest.
There’s the thing though. If someone really was disciplined, took their lunch, but put that money into a managed share fund, assuming it earns just 7% (kind of low for shares) and compounding the interest.
That’s 72.50 a week.
After 30 years you would have invested around 113000 and with compound interest you’d have approximately 385000. After 40 years you would have invested around 151000 and should have about 830000.
Two tricks to this. You have to actually do it and not just talk about it. Secondly, you had to start 30-40 years ago. It’s the long term compounding that does the work.
I wish this was something I learnt a whole lot earlier. Trying to get my kids to invest every week now, but despite the figures, they also have trouble picturing themselves 30 years from now.