For our 24x7 website we have a number of tables that record session information, including each page a user visited. this table averages around 4-5mil records.

To keep the size manageable, we run a job every hour which moves records older than 60 days into an archive database. We used to run it every day but found that it was causing blocking and timeouts during the large delete operation. Running it every hour means that a lot of small deletes occur.