# Product Relationship Matrix — Reference Guide

## How to Read Purchase Sequence Data

If you have order history data, run this analysis:
1. For each order containing Product A, count how many also contain Product B
2. Calculate co-purchase rate: (orders with A+B) / (orders with A)
3. Any co-purchase rate >15% indicates a strong natural pairing

| Co-purchase rate | Relationship strength | Recommended action |
|-----------------|----------------------|--------------------|
| >30% | Extremely strong | Feature as "frequently bought together" on product page |
| 15–30% | Strong | Include in cart cross-sell |
| 8–15% | Moderate | Include in post-purchase email |
| 3–8% | Weak | Test as checkout add-on only |
| <3% | Negligible | Not a recommended pairing |

## Category-Specific Pairing Patterns

### Beauty & Skincare
Natural pairings follow the "routine stack" logic:
- Cleanser → Toner → Serum → Moisturizer → SPF (AM)
- Cleanser → Treatment (retinol/exfoliant) → Moisturizer (PM)

Cross-sell angle: "Complete your routine" — position each product as the missing step in the buyer's current routine.

### Electronics & Tech
Pairings follow the "ecosystem" and "protection" logic:
- Device → Case/cover → Screen protector → Extended warranty
- Device → Cables/chargers → Accessories → Replacement consumables

Cross-sell angle: "Protect your investment" (protection) or "Works perfectly with" (ecosystem).

### Food & Supplements
Pairings follow "stack" and "bundle meal" logic:
- Protein powder → Shaker bottle → Pre-workout → BCAAs
- Coffee → Grinder → Coffee scale → Reusable filter

Cross-sell angle: "Better together" — cite the combined benefit (e.g., "Pre-workout + protein = better performance AND faster recovery").

### Home & Kitchen
Pairings follow "complete the set" and "maintenance" logic:
- Cookware set → Cooking utensils → Cutting board → Cookbook
- Air purifier → Replacement filters → Air quality monitor

Cross-sell angle: "Everything you need" or "Keep it working perfectly."

## Post-Purchase Upsell Timing Reference

| Product type | Avg depletion time | Replenishment email timing |
|-------------|-------------------|--------------------------|
| 30-day supplement (1/day) | 30 days | Day 21 |
| 60-capsule supplement (2/day) | 30 days | Day 22 |
| Skincare serum (30ml, daily) | 60–90 days | Day 50 |
| Coffee (250g bag, 1 cup/day) | 25 days | Day 18 |
| Air purifier filter | 6��12 months | Month 5 |
| Razor blade cartridges (5-pack) | 5–10 weeks | Week 4 |
| Pet food (5lb bag, small dog) | 30–45 days | Day 28 |

## Bundle Pricing Psychology

The "magic number" for bundle savings is 15–20%:
- Below 10%: Buyers do the math and find it not worth the mental effort
- 10–20%: Clear value; most buyers don't calculate, just feel the deal is good
- Above 25%: Buyers wonder what's wrong with the bundled products (too good = suspicion)

Bundle framing options:
- Price-anchor framing: "Buy separately: $87 | Bundle price: $72"  
- Savings framing: "Save $15 when you buy together"
- Outcome framing: "The complete [result] kit — everything you need"