TL;DR
A short, sharp promo creates urgency without training customers to wait. Fifteen minutes of 15% off beats an always-on 10% that quietly eats your margin every day.
Always-on discounts feel safe. They also reset customer expectations. When every visit is "on sale," your full price stops meaning anything — and your margin never recovers.
Why flash beats always-on
A 15-minute window concentrates demand into a slot you choose — slow Tuesday lunch, pre-dinner lull, rainy hour. You spike orders without permanently marking down your menu.
How to run it
Pick one or two slow movers with healthy margin. Set a tight window and a clear cap. Promote inside the app notification, not as a store-wide banner on your hero items. Measure incremental orders, not just redemptions.
What to watch
If the same customers redeem every flash, you're rewarding loyalty you already had. Track new vs repeat on promo orders. Kill the coupon shape that only feeds regulars.
Summary
Scarcity protects margin. Short promos on the right items beat permanent discounts on everything.
