The "envelope system" is a well-known money-saving strategy.
The idea is to save for your goals—a down payment for a home, a new car, a vacation—using a series of envelopes. Every payday, you peel off a little cash and deposit it in your envelopes, slowly chipping away at your goals.
Things have gotten a little bit more sophisticated over time, but the time-honored envelope system is the same idea behind the growing trend of goals-based investing. In investing parlance, it's known as "mental accounts," where each of your financial goals are funded and invested independently. Each goal, because it has a unique time horizon, has its own asset allocation and its own risk profile.