depends on your lifestyle and income I guess. If you have high income and high expenditures you have the choice between immediate pleasures or early retirement, and that choice isn't so clear cut imo.
for software guys like mmm I'd wager that it's better to take the time and energy used on frugality and instead try to develop alternative income streams, which ironically is exactly what mmm did.
regrets over $10-30 purchases seem like a complete waste of time to me... https://www.newyorker.com/magazine/2016/02/29/mr-money-musta...
The point is find eliminate spending on stuff that doesn't really make you happier, and focus on the things that do. Also, find cheap hobbies, reading, etc. etc.