• Look up an illustrative local preservation-review interval by broad digital format class.
• Apply the same explicit rule consistently during ingest, quality control, reporting, or preservation planning.
• Expose records that need human review without silently rewriting the source data.

The returned value is a policy-review cadence, not evidence that every object should be migrated automatically when the interval expires.^[1]

• No universal migration interval exists; format risk, rendering dependencies, validation evidence, authenticity, and institutional policy should drive action.
• Preserve the original value and record the rule version when using this result in an archival workflow.

• Format Obsolescence Watchlist Risk Score Rater

  Use Format Obsolescence Watchlist Risk Score Rater to apply a transparent local watchlist heuristic to format age, proprietary status, emulation dependence, and validation-tool availability. Choose this tool when you need to look up an illustrative local preservation-review interval by broad digital format class.

• Digitization Priority Score

  Use Digitization Priority Score to calculate a normalized 0–100 digitization priority score from significance, condition risk, demand, and nonnegative relative weights. Choose this tool when you need to look up an illustrative local preservation-review interval by broad digital format class.

• ISO 8601 Date Interval Format Validator

  Validate a practical ISO 8601 interval subset of the form start/end. It checks Gregorian calendar dates (including leap years), clock and UTC-offset ranges, reduced-precision dates, and non-mixed calendar or week durations; it does not compare endpoint chronology.

• Web Crawl Frequency by Site Change Rate Recommender

  Apply a local planning policy to recommend a web-archiving crawl cadence from the weekly page-change fraction: monthly below 0.5%, weekly below 2%, twice weekly below 8%, and daily otherwise. Adjust the thresholds to match collection risk and crawl budget before operational use.

• Format Obsolescence Watchlist Risk Score Rater

  Rate preservation format obsolescence risk on a capped 0-100 scale (two points per year since release plus twenty for proprietary formats, twenty-five when emulation is required and fifteen when validation tooling is lacking) with low, moderate, high and critical tiers.