Every brand's 'medium' is a different size and returns are the tax
“I'm a medium in one store, an XL in another, and a mystery online. I order two sizes of everything and return half — I literally keep notes in my phone about which brands run small.”— Hacker News ↗
Sizing tools are merchant-side widgets (True Fit) that only work on stores that installed them and hoard the data. Nobody serves the buyer's side: a personal fit journal — brand, garment, size bought, verdict — that answers 'what size am I at Uniqlo?' at checkout time.
Anyone who shops for clothes online
Build a personal clothing-fit journal in Next.js. Log entries: brand, garment type, size bought, fit verdict (too small / fits / too big) and an optional note. Show a per-brand summary ('runs small — size up') and a fast search so you can check a brand mid-checkout on your phone. First 3 steps: (1) the entry form + localStorage-or-SQLite persistence, (2) per-brand aggregation with a verdict heuristic, (3) instant brand search styled for one-handed phone use.