> For the complete documentation index, see [llms.txt](https://sourcesheets.gitbook.io/sourcesheets-new-seller-blueprint/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sourcesheets.gitbook.io/sourcesheets-new-seller-blueprint/part-4-sourcing-and-buying-your-first-products/7.6.8-case-study-8-passes-today-fails-tomorrow.md).

# Case Study 8: Passes Today, Fails Tomorrow

At first glance this product looks acceptable. Buy cost is £11.50, current Buy Box price is £19.99, a profit of £2.60 a unit at a 23% ROI, both clear of the Gate 1 and 2 floors. Demand appears healthy in isolation, around 180 units a month against the 30-day window Gate 3 looks at. There are no immediate red flags in eligibility, competition, or fees. Assessed purely on the last 30 days, it would clear all seven gates without resistance.

## Historical Behaviour Tells a Different Story

Looking beyond the 30-day window Gate 4 checks reveals the real risk. Pulling twelve months of price history shows the same pattern repeating: a sharp rise driven by seasonal demand and promotional activity, followed by an abrupt collapse, roughly 55% down from the peak, once demand fades. The 30-day gate window this Blueprint uses doesn't catch this on its own, it only shows that the current climb hasn't reversed yet.

## Seasonal Demand and Timing Risk

This is a classic seasonal item. Demand spikes around a narrow window, sellers flood the listing, prices compress, and then collapse once the season ends. The current price uplift exists only because supply has temporarily thinned. As soon as new sellers restock, Amazon intervenes, or demand normalises, margin erosion of the kind seen in past cycles is almost guaranteed.

> 📸 **Screenshot needed:** historical price chart showing the seasonal spike-and-collapse pattern

## Why This Is Easy to Miss

Tools show what's happening now, not why it's happening, and the standard 30-day Gate 4 window is built for ordinary volatility, not a 12-month seasonal cycle. Without pulling the longer history yourself, this product appears stable and profitable. Beginners often mistake temporary recovery phases for genuine stability, entering just as the next price drop is imminent.

## Core Lesson

Passing analysis doesn't mean "safe," it means "not obviously bad right now." A product can mechanically clear every numeric gate on a 30-day view and still be a Park / Monitor decision once you check further back. Seasonal and historically volatile products can pass every gate today and still fail tomorrow. This is why pulling price history beyond the standard window, and restraint when it shows a repeating pattern, matter more than the gate result alone. A clean snapshot is a starting point, not a guarantee.