[dba-SQLServer]Qualifying Object Names

Just a general question.  Some books suggest that when writing code you 
should always qualify objects with the owner name (eg dbo.tblCustomers).

How far should this be taken?  Should I be doing this for every field in 
every sproc? or are there sets of guidlines?  What benefits are there of 
including the owner name?

Regards

David Emerson
DALYN Software Ltd
25b Cunliffe St, Johnsonville
Wellington, New Zealand
Ph/Fax (877) 456-1205