Record retrieval from former affiliates, translation, and the availability of managers who can confirm duties for older periods. These run on other organisations' timetables. Legal review of the qualifying year should happen once those records are in, not after a filing plan is already committed.
Front-load the retrieval
Start document requests in the first week, because they are the step nobody can accelerate later. Set a point at which the case is reassessed on whatever has arrived. Note also that periods of authorised employment in the United States can affect how the maximum period of stay is counted for this classification, which is a question for counsel on the individual history rather than a rule to apply yourself.
Start the document requests in the first week, since they are the step nobody can accelerate later and the one most often begun last. Set a point at which the case is reassessed on whatever has arrived rather than waiting indefinitely for a record that may not exist. Legal review of the qualifying year belongs after the records are in, not after a filing plan has been committed to.
Note also that periods of authorised employment in the United States can affect how the maximum period of stay is counted for this classification, which is a question for counsel on the individual history rather than a rule to apply from a summary. Keep the retrieval log current.