The quiet shrink
Ice cream cartons went from half-gallon to 1.5 quarts; chip bags gained air; "family size" shrank twice in a decade. The list price stays, the unit price jumps 10–25%. Because the sticker is constant, only unit-price buyers notice — which is exactly why brands do it gradually.
The defense is one habit
Check the unit price (shelf tag corner or this calculator) on your ten most-bought staples and remember the number. When it jumps without a price change, you have caught the shrink — and can switch brand or size while the sticker still looks innocent. Ten numbers is all the memory this requires.
Reprice on a schedule
Prices drift; a unit-price audit of your staples twice a year (five minutes in the store's app or aisle) keeps your mental catalog honest. The alternative — brand loyalty to a shrinking package — is a subscription to paying more while feeling the same.