Glossary
Opportunity cost
What you gave up by choosing this instead of the next best thing.
A side hustle netting $800 a month for twenty hours a week is not free money if those hours could have gone into skills that raise your salary by $20,000 a year.
It is the most consistently ignored cost in wealth-building, because it never appears on a bank statement. Every technique on this site should be judged against what else those hours and that capital could do.