Here are the most common migration strategies that are performed:
A single pass migration strategy that will move the entire mailbox in one pass after MX records are cutover. A typical scenario consists in cutting over on a Friday evening and migrating during the weekend.
A multi-pass migration consists of pre-staging a majority of the data prior to cutover and doing a Full (Delta) Pass after cutover.
How do I configure a multi-pass migration?
A quick-switch migration consists of pre-staging only the newest emails. New emails are accessible immediately at time of cutover by users and the remaining data is backfilled over time.
How do I configure a Quick-Switch Migration?