1. I like to have really small defaults for initial and next extents. That way, I can tell when my developers sneak a table into production and don't tell me (it will extend really quickly). I usually set maxextents to unlimited.

2. I set the default pctincrease=1 on the tablespace for a couple of reasons. First, if pctincrease=0, then smon won't kick in and coalesce the free extents. Second, it also helps me catch my developers sneaking something into production.

3. via alter table xyz deallocate unused
Check out [url]http://technet.oracle.com/docs/products/oracle8i/doc_library/817_doc/server.817/a85397/statem2a.htm#2056065[/url]