How old is a cost-of-living number? Check three dates

Find the period being measured

A rent report published this month may describe contracts from an earlier year. Record the observation period separately from its publication date. For a tariff, record when it becomes effective and whether it applies to your chosen product. A recently updated web page is not enough to establish that every number on it measures today’s market.

Keep retrieval separate from freshness

The date Lifovra retrieved a source describes collection, not the age of the underlying prices. Re-downloading the same report does not create new observations. When two sources disagree, first check whether they measure different periods or cohorts. Do not choose the newest-looking timestamp without reading what the timestamp actually refers to.

Decide what needs a current quote

Use older evidence as dated context, then replace decision-critical items with compatible current offers where possible. Preserve both the old period and the new quote date. Do not silently inflate a historical rent by a national index and call it a new city median. If a category cannot be refreshed, retain an uncertainty label and show which part of your personal decision still needs checking.

Sources and further reading

• Lifovra — methodology and limitations