Answers to Skip download if files exist in wget? say to use -nc, or --no-clobber, but -nc doesn\'t prevent the sending of the HTTP req
-nc
--no-clobber
It appears you are using incompatible options, I get the following warning on wget 1.16 linux:
$ wget --no-clobber --convert-links http://example.com Both --no-clobber and --convert-links were specified, only --convert-links will be used.