Avoid refreshing collections unless you absolutely have to

Only use the Refresh method when you need to. It is generally an expensive operation relative to most DAO operations and should be used sparingly.

DAO has many collections on its various objects. Because some of those collections are based on data stored in the database, the DAO collection can get out of date if someone else changes something in the database. For example, if some other user adds a table, it won't immediately appear in the Tabledefs collection. The Refresh method of each collection forces DAO to fill the collection again with the latest information in the database.