[dba-SQLServer] To Drop or not to Drop, that is the question

I have a largish database, currently 92 million records.  I get an update
with ~1 million records every week.  At what point does dropping /
rebuilding the indexes become more expensive than adding the records with
the index in place?  Is there a tool to predict such a thing?

John W. Colby
Colby Consulting
www.ColbyConsulting.com