Definition
Lifestyle Inflation
The tendency to spend more as you earn more, so raises never turn into wealth.
Lifestyle inflation, or lifestyle creep, is when your spending quietly rises to match every raise or bonus: a nicer apartment, a newer car, more subscriptions. It feels reasonable one upgrade at a time.
Left unchecked, it means a higher income produces a fancier life but no more savings. The defense is to bank each raise before you get used to it, widening the gap between what you earn and what you spend.