Just like how you store your leftovers in the fridge to keep them fresh, mixed drinks require proper storage to maintain their flavor and quality. If you store your mixed drink in a sealable container and keep it in the coldest part of the fridge, it will last longer than if you leave it out at room temperature. On the other hand, if you store it in a container that's not airtight, you might end up with a flat and stale drink.
A good example is when you order a pitcher of margaritas at a restaurant, and they store it in the fridge until you're ready for a refill. If stored properly, a pitcher of margaritas can last for several hours without losing its flavor. However, if you were to leave it out at room temperature, it would likely go flat and warm within an hour.
