The binder clip that saved my grocery cash system

For years I kept cash in those labeled envelopes for groceries, gas, fun money, you name it. The problem was I always forgot which envelope had what left, and I'd dig through my purse at the register like a maniac. Last month in Portland I watched a cashier organize her entire drawer with binder clips on each stack, and it hit me. Now I clip my receipts to the front of each envelope as soon as I buy something, so I see exactly what I spent and what's left without opening anything. It also stops me from grabbing the wrong envelope for a coffee run, which used to wreck my whole week's plan over 4 dollars. Has anyone else found a weird physical trick that makes your cash system actually stick? I'm curious if it's just me who needed a visual cue that bad.