emerge -uDN world - How Often?

That’s the question.
What is the standard or practiced intervals suggested for doing a

emerge -uDN world

Please post your practices and why.

Thank You

In the Opinion of Gentoo user miqorz “I haven’t emerge -Ud world’d yet and i dont plan on it.”

My Research says

eix-sync

So emerge will see New packages as well

Some people have suggested
emerge -uDv

Gentoo Wiki Suggests

Updating your system
Simply doing emerge world will most likely not have the desired result when attempting to upgrade your system. Often a better way to do this is by using :
emerge -uavDN world
Here is an explanation of the extra switches and what they do:
u: The update switch is often included for clarity, but is the default action when using the “world” or “system” package specifications.
a: (ask) This is highly recommended on any emerge. It will tell you what it’s planning to do before it does it. This gives you a chance to scan the list to make sure nothing is terribly wrong.
v: (verbose)[optional] This gives you more verbose output. It is technically optional, but it is often helpful.
D: (deep)The world package is not a list of every single package on your system. Only the ones you have emerged. For example, if you do emerge gnome there will be many dependencies installed on you system as well as gnome-base/gnome; however, only gnome-base/gnome will be recorded in the world files. Using D scans through the dependencies for updates too.
N: (newuse)[optional] This is the most optional of them all. Essentially what it does is check for any changes in the USE flags. This would normally be the case if you changed something in /etc/make.conf or maybe /etc/portage/package.use. For example, if you added USE=“java” in /etc/make.conf and mozilla-firefox was originally emerged with the default setting (-java), then adding N would cause this command to re-emerge mozilla-firefox with the new USE variables. This should probably be used only when you want to rebuild all packages with changed useflags, which is not likely part of your routine updates. See USE Flags for more information.
e: [highly optional] This option pretends that nothing is installed, it is only useful when upgrading a part of your toolchain. The emerge -e command is perfectly equivalent to a stage 1 installation. Use it only if you know what you do. Check out this post for more information.

How often? it depends on you needs. If you want a stable system and do not plan to in the future to put additional software, you can configure system and then do not update.

If you plan update system, install new software and use binary update - my opinion 1 update per month.

Apologies…
Just realized that I didn’t thank you for your responding post.

Thank You! :^)