Laura:

Yes, Day Ends should indeed be run daily. Usually the best time is first thing in the morning after the nightly back-up process but before any work is done for the day.

Retrieving from the sub-ledgers to the GL is more a matter of choice. In simpler situations where volumes are low and they don't rely on GL reporting, once a month is common. But in more complex situations it may make sense to retrieve more often, perhaps weekly. This would allow monitoring of things like clearing accounts and allow corrective action sooner. However I don't know anyone retrieving on a daily basis. Beyond the issue of too many batches in the GL, daily financial statements aren't very meaningful.