Newest version of programms?

[kleinerdrache]

Hello,
how can I make sure that there is always the last version of a programm installed?
It seems, that emerge installes any of the versions, I couln't get out the rules for the decision emerge makes.

I.e. when I try emerge -p tetex it tells me, that it will install 1.0.7 instead of 2.0.2 which is also available.
The same for balsa: emerge -p tells me to install 2.0.11, but 2.0.12 is also available.

I know, I could install the new version directly by telling emerge which ebuild file to use.
But how can I make sure for the dependencies that the newest version gets used?

Now I have installed gnome, all of it, and I think there are many ports which do not use the newest version.
Is there something here, to let them install the newest version of all the portages, or upgrade to the newest version?
How can I do that?
Can I set up something in the make.conf file to tell emerge always to use the last version?
Thanks,
Martin

[fusion]

do a emerge sync
then do a emerge -Dup world