>If I add 1000 records in a table and remove all of them. Does SQL Server keep that empty space or will it recycle it? By that, I mean, once in a while, is there any reason to do a database compress?

You've to be careful with word 'compression' because SQL 2008 includes new feature the Data compression. See http://blogs.msdn.com/sqlserverstorageengine/archive/2008/01/27/compression-strategies.aspx for some interesting info.