Why Discounting Destroys More Than Margin
Everyone knows discounting erodes margin. Fewer people understand the second-order effects on Google Ads performance, customer quality, and long-term profitability.
The obvious cost of a 20% discount is 20% less margin per order. That's the number everyone calculates. But it's not the real cost.
The real cost includes what happens to your Google Ads account, your customer acquisition mix, your return rates, and your repeat purchase behaviour. These second-order effects often exceed the direct margin loss.
A 20% discount doesn't cost you 20%. It costs you 20% + algorithmic confusion + worse customer quality + higher returns + trained discount-seekers. That's often 40-50% of the value you thought you were creating.
Effect 1: Algorithm Contamination
When you run promotions, conversion rates spike. Google's algorithms see this and think: "This is what good looks like." Then the promotion ends, conversion rates drop, and the algorithm panics.
The result:
- Smart Bidding becomes volatile as it chases the promotional baseline
- CPCs inflate as the algorithm tries to recapture "lost" conversion rate
- Learning periods reset, making the next 2-3 weeks less efficient
- ROAS targets that worked pre-promotion now seem "unrealistic"
The hidden cost: It takes 4-6 weeks for most accounts to stabilise after a major promotional period. During that time, you're paying Google to figure out your new baseline.
Effect 2: Customer Quality Degradation
Promotions attract different customers. Specifically, they attract customers who buy on price. These customers have fundamentally different economics:
Full-Price Customers
- • Lower return rates (12-15%)
- • Higher repeat purchase rate
- • Less price-sensitive on reorder
- • 2.1x average LTV
Discount Customers
- • Higher return rates (22-28%)
- • Lower repeat purchase rate
- • Wait for next discount to reorder
- • 0.8x average LTV
When Google sees your promotional conversion spike, it optimises to find more of those customers. You've just trained the algorithm to prioritise discount-seekers.
Effect 3: Return Rate Amplification
Promotional purchases have higher return rates. Not because the products are different, but because the purchase motivation is different.
- Impulse buying increases. "It's on sale" overrides "do I actually need this?"
- Multi-size orders spike. "I'll order both sizes and return one" becomes common.
- Gift returns surge. Discounted items are often speculative gifts that get returned in January.
A typical 20% discount period sees return rates increase by 30-40% relative to baseline. That's not just lost revenue; it's reversed revenue with processing costs attached.
Effect 4: Conditioned Behaviour
The most expensive effect is invisible: you're training your best customers to wait.
Regular discount cycles teach customers:
- "If I wait 4-6 weeks, there'll be a sale"
- "Full price is for suckers"
- "I can always get a code if I abandon my cart"
This creates a ratchet effect. Each promotion trains more customers to wait for the next one. Revenue increasingly concentrates in promotional windows. Full-price conversion rates decline. And the only way to maintain volume is to promote more frequently.
The end state is a brand that can only sell at discount. We've seen this pattern destroy contribution margin by 60%+ over 18 months, even while revenue grew.
What to Do Instead
Discount strategically, not habitually
If you must discount, do it rarely and with purpose. Clearance is valid. Training customers to wait is not.
Separate promotional traffic
If you run promotions, run them through dedicated campaigns with separate budget. Don't let promotional spikes contaminate your core campaigns.
Measure true promotional cost
Include return rate differentials, algorithm recovery time, and LTV impact. A "successful" promotion often has negative ROI when properly measured.
Build value, not urgency
Invest in product quality, customer service, and brand positioning. Brands that compete on value don't need to compete on price.
Related Reading
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