Why Most Aftermarket Catalogs Don’t Scale - and How to Fix Them
Make Room for Growth
For more than 25 years, I’ve lived at the intersection of catalog data, vehicle fitment, inventory strategy, and online marketplaces.
At CarParts.com, I led teams responsible for:
Over 1 million SKUs
100+ million vehicle application records
P&L ownership across eBay, Amazon, and Walmart
Growing eBay Motors into the #1 Parts & Accessories seller for five consecutive years
Becoming the #1 GMV seller on eBay in all of North America
What I learned along the way is simple - and uncomfortable:
Most aftermarket businesses don’t have a growth problem.
They have a data and execution problem.
The Hidden Cost of Bad Fitment and Catalog Data
Returns, cancellations, poor conversion, slow inventory turns - these are often treated as separate problems.
They aren’t.
They usually trace back to:
Incomplete or incorrect fitment
Overlapping or duplicated SKUs
Weak attribute structure
Listings that don’t clearly communicate what fits and why
At scale, even a 1-2% fitment error rate turns into:
Millions in avoidable returns
Customer trust erosion
Marketplace suppression
Excess working capital tied up in the wrong inventory
Fixing this isn’t about “cleaning a spreadsheet.”
It requires systematic catalog discipline.
Marketplace Success Is Earned - Not Uploaded
During my time owning marketplace P&L, one thing became very clear:
Marketplaces reward precision, not volume.
Winning on eBay, Amazon, or Walmart isn’t about listing more SKUs - it’s about:
Correct category and leaf placement
Titles and item specifics built for search intent
Pricing guardrails that protect margin
Shipping rules that scale profitably
Listings that reduce buyer confusion
At CarParts.com, marketplaces represented 34% of total revenue at peak - and that only happened because catalog, pricing, and operations were tightly connected.
Inventory Growth Without Strategy Is Just Risk
One of the most misunderstood areas in aftermarket is inventory expansion.
Adding SKUs without:
Fitment depth
Demand validation
White-space analysis
Bundle strategy
…doesn’t create growth.
It creates dead inventory.
Some of the most impactful work I led included:
Identifying private-label white space
Reducing duplicated SKUs across PL lines
Building virtual bundles and kits that increased AOV and reduced shipping cost
Actively managing slow-moving inventory before it became a warehouse problem
The goal was never “more SKUs.”
The goal was faster turns and healthier cash flow.
Why I Started PartsAdvisory
After decades inside one of the largest aftermarket organizations, I saw the same challenges repeated across the industry - manufacturers, distributors, and sellers all struggling with:
Catalog accuracy
Marketplace execution
Inventory risk
PartsAdvisory exists to solve those problems before they show up on your P&L.
We focus on three things:
Improve Your Data - fitment, attributes, and catalog structure
Optimize Your Marketplace - listings, pricing, compliance, and scale
Grow Your Inventory - smart SKU expansion, not blind assortment growth
Because when those three work together, results follow.
Final Thought
If you’re dealing with:
Rising returns
Suppressed marketplace performance
Inventory that doesn’t move the way it should
…it’s not bad luck.
It’s fixable.
And it starts with getting the fundamentals right.
If you want to validate your catalog before scaling, I offer a free Catalog Health Review focused on fitment accuracy, attribute completeness, and duplicate SKU risk. Contact me and I’ll share next steps.