Limitations & Known Issues
We believe you should know what we can't do as clearly as what we can. This page documents our limitations, known issues, and edge cases.
Why We Publish This
Trust is built through honesty. By being upfront about our limitations, we help you use our tools appropriately and set realistic expectations. If we don't tell you where we struggle, we're not being fair to you.
Core System Limitations
We Estimate, We Don't Guarantee
CriticalOur valuations are statistical estimates based on market data. They are not appraisals, guarantees, or legally binding assessments.
- •Actual sale prices may differ significantly from our estimates
- •Unique, rare, or one-of-a-kind items have higher uncertainty
- •Market conditions can change faster than our models update
We provide confidence intervals and uncertainty scores. Always use the range, not just the point estimate.
Health Screening is Risk Estimation
CriticalWe assess chemical and material risk using databases and models. We do not physically test products.
- •A 'low risk' score is not a safety certification
- •Products may contain hazards we cannot detect from metadata
- •Individual sensitivities vary—what's safe for most may not be safe for all
We clearly label our assessments as 'risk estimates' and recommend professional testing for high-stakes use cases (children's products, medical items).
Data Has Blind Spots
Our training data is biased toward English-speaking markets, mainstream brands, and recent years.
- •Lower accuracy for non-US/UK markets
- •Vintage items (pre-2010) may be underrepresented
- •Independent/artisan brands often lack data
- •Non-fashion categories have less training data
We're actively expanding data sources. Category-specific accuracy metrics are published on our Methodology page.
What We Don't Do
To be crystal clear, here are capabilities we do not offer:
Authentication
We cannot verify if an item is authentic or counterfeit. Use dedicated authentication services.
Physical Inspection
We cannot assess actual condition, smell, stains, functionality, or physical defects.
Legal Appraisals
Our valuations are not suitable for insurance claims, estate planning, or legal proceedings.
Real-Time Auction Tracking
We don't track live auctions; our pricing reflects historical completed sales.
Guarantee Sale Prices
Our estimate is a prediction, not a guarantee. Actual sale prices vary.
Category-Specific Limitations
Luxury/Designer Items
±12% for verified items, higher for unverified- Cannot verify authenticity from data alone
- Limited edition items may be mispriced
- Requires authentication service for high-value items
Vintage/Antique
±18% average, varies widely by item- Less historical data available
- Condition assessment is particularly subjective
- Provenance significantly affects value but is hard to verify
Electronics
±7% for common items, ±15% for accessories- Rapid depreciation makes predictions time-sensitive
- Functionality cannot be verified remotely
- Battery health significantly affects value
Furniture
±15% average- Shipping costs not factored into valuation
- Local market conditions vary significantly
- Assembly condition unknown
Children's Products
Health screening: risk estimation only, not safety certification- Safety standards change frequently
- Age of recalls may not be in our database
- Physical inspection strongly recommended
Known Issues
Active issues we're aware of and working on (or accepting as inherent limitations):
Trending Item Lag
Items that suddenly become viral (TikTok trends, celebrity endorsements) may be undervalued for 7-14 days until our models catch up.
Check demand signals and trending indicators; use human judgment for social media-driven trends.
Ongoing - inherent limitation of batch model updates
Condition Relies on Seller Honesty
We cannot verify the actual physical condition of items. Our condition-based pricing assumes accurate seller reporting.
Request photos and detailed descriptions. Our confidence score accounts for condition uncertainty.
Exploring computer vision integration (no ETA)
International Shipping Not Factored
Valuations reflect market price but do not account for shipping costs, import duties, or regional availability.
Factor in shipping manually; our regional price APIs provide some localization.
Q2 2025 - regional shipping estimates
Bundle Pricing Complexity
Lots and bundles are priced as sum of parts, which may undervalue curated collections or overvalue random lots.
For curated collections, use single-item mode and apply manual adjustment.
No current plans - complex problem
Edge Cases & Special Situations
| Situation | System Behavior | Recommendation |
|---|---|---|
| Items with no sales history | Returns wide confidence interval and 'low confidence' flag | Consider manual research or professional appraisal |
| Counterfeit/replica items | May price as authentic if not flagged. We do not authenticate. | Use authentication services for high-value designer goods |
| Items with recalls | Some recalls flagged; database may be incomplete | Check CPSC recall database independently for children's products |
| Regional items (e.g., Japan-only releases) | May lack comparable data; defaults to similar global items | Use regional marketplaces for more accurate comps |
| Very high value items (>$10,000) | Higher uncertainty; auction dynamics not modeled | Professional appraisal recommended for insurance/estate purposes |
Found an Issue We Haven't Listed?
We want to know about problems. If you've encountered a limitation, inaccuracy, or unexpected behavior that isn't documented here, please tell us.