61 days in total; the 15 shown are block problems first, then the longest delays.

1. Extract (monthly, from AWS): seven checks on every month, including continuous block numbers, no duplicate blocks, and transfers with no missing amount or address.
2. dbt (monthly): 21 tests per month, including unique keys, accepted values, no block gaps and a reconciliation that the daily cube adds up to the raw transfers exactly. A month that fails is not uploaded.
3. Freshness: the load log for last month must be less than 35 days old (warning) or 62 days old (error).
4. This page: a day is late or rewritten if its slowest row was written more than twice the usual delay (24 hours) after its block. Either the data arrived late, or the source rewrote that day afterwards; both mean the day's numbers may have changed after they were first published. What these days look like is shown on the Investigations page.

The source data is AWS Public Blockchain Data, which AWS labels experimental. That is why completeness is checked from the data itself: block numbers are sequential, so a gap is visible without trusting the loader.