As a gentoo desktop user, update pkg though emerge is my daily job. I've set 'emerge --sync && emerge -fuDU @world' as a cron job, and I'm insisted in doing 'emerge -avuDU @world' manully everday.
Here's my question, I've noticed that 'emerge -avuUD @world' and 'emerge -avguDU @world' will result in some differences, normal, 'guUD' will result in less pkgs to be updated. And after 'guDU' finished, if I run 'uDU', seems still some pkgs need to be updated. I'm not sure why this is. Is someone familiar with this? And is there any other better way to upgrade for daily desktop mechine?

