That depends on the institutions holding the records, not on the program. Foreign banks can take weeks to retrieve archived statements, and closed accounts may take longer or produce nothing. Official descriptions of the process duration are not guarantees, so no combined timeline should be promised. Start record requests before the application, since retrieval is the slowest part.
Track requests like a project
Keep a simple log of every record request: institution, date sent, contact used, and what came back. Follow up on a fixed schedule instead of waiting for replies that may never arrive. When a document is refused or unavailable, record that outcome and move to the next best evidence rather than stalling the whole file.
This log also becomes a useful explanation of why a particular gap could not be closed. Add one further practice to that log: record what you will do if a request is refused or unanswered, at the time you send it. The alternative evidence, the person who could confirm the same fact, or the explanation that would stand in its place is far easier to identify while the item is fresh than months later when the absence has become an obstacle.
A log with a fallback column keeps a file moving. Hypothetical example: a household logs eleven record requests with a fallback noted against each, and when three go unanswered the file continues on the alternatives already identified rather than stalling while somebody works out what to do instead.