Standardize country names, catalog systems, and currency symbols so filters remain precise. Use ISO dates for issue and postmark fields. Normalize color terms and perforation gauges to defensible ranges. Align catalog references with explicit prefixes like Scott, Michel, Yvert, or Stanley Gibbons, avoiding ambiguous shorthand. Provide lookup lists for cancel types, paper, and watermark. These guardrails dramatically reduce duplication, accelerate data entry, and prevent future reconciliation headaches that can derail inspiring research progress.
Condition deserves granular fields: gum state, hinge status, centering, thins, tears, creases, and reperfs. Separate numeric grades from textual remarks to keep sorting clean. For cancellations, capture type, ink color, legible text, and date certainty. Provenance can note purchases, trades, and prior owners, which often surface valuable context or attributions. These details transform similar-looking pieces into distinct stories, guiding valuation, exhibit narratives, and targeted upgrades grounded in transparent, auditable information.