The size allocation decisions you make are important, because it is difficult to reclaim storage space after it has been assigned. You can always add space; however, you cannot deallocate space that has been assigned to a database, unless you drop the database.
You can estimate the size of the tables and indexes for your database by using sp_estspace or by calculating the value. See Chapter 4, “Determining Sizes of Tables and Indexes,” in the Performance and Tuning Series: Physical Database Tuning.
