Every document and written answer carries its own deletion date. For a fixed retention period, the date is the day your client sends the item plus the period. Items sent on different days have different dates, so the clock runs per item and not per request.
The first period counts in plain days. A period of 1 year is 365 days, so a leap day inside it makes the date fall one calendar day earlier. A law's period counts a whole number of years as calendar years.
For As long as they're a client, there is no date at first. The date is set when you mark the relationship as ended. Without a law period, the documents are deleted in the next daily run after that end date. With one, the date is the end date plus the law's period.
Four things change a date:
Deletion runs once a day. An item is deleted in the first daily run after its date and time arrive, which can be early the next morning. Every deletion is recorded.
You can see a date in two places. A client's folder shows it on the request's card. The Retention queue shows it as promised until during the last 15 days.
For example
Amaltas Deshmukh & Co sends Farhan Qureshi a request on 1 July 2027 with a retention period of 1 year. Farhan sends part of his documents on 1 July 2027 and the rest on 8 July 2027. The first documents are due on 30 June 2028, which is 365 days after 1 July 2027. The rest are due on 7 July 2028, which is 365 days after 8 July 2027. Each goes in the first nightly run after its date. A row for Farhan opens in the Retention queue 15 days before the earlier date.