Rule 5 of 19 · Chapter I — Spend Less Than You Earn
Bank most of every raise
Why this rule exists
The raise you fought for has a quiet way of vanishing. Income rises, and spending rises to meet it almost automatically: a nicer apartment, a bigger car payment, habits that were treats becoming defaults. This is lifestyle creep, and it explains why people who earn far more can feel just as stretched as they did years ago. The cruel part is that once an expense becomes normal, cutting it feels like a loss, so the higher spending tends to stay even when the income does not.
In practice
When your income goes up, decide in advance where the new money goes before it touches your lifestyle. A simple split works: let some improve your life now and send the larger share straight to saving or debt, automatically, so you never adjust to seeing it. Enjoy some of every raise, because denial forever is not the goal, but keep your fixed costs, especially housing and cars, from climbing every time you earn more. Grow your saving rate, not just your standard of living.
When it doesn't apply
If you have been genuinely underspending, skipping medical care, living somewhere unsafe, missing the years with your kids, a raise should buy some real life back. Frugality is a tool, not a religion. Creep is the problem, and a deliberate, chosen upgrade is not.