How do you manage space consumed by /usr/pkg

[Mayuresh <mayuresh%acm.org@localhost>]

Even if one is conservative about installing packages, over a long period
of time one might accumulate a lot of packages which may not be in active
use and disk space crunch may require pruning some of them.

If it is really after a long time, one may even consider pruning all pkgs
and start afresh.

But are there / can there be tools that would help one manage space
better?

E.g.

- Can we see installed packages sorted by their space share?

- Can we see installed packages by their pkgsrc category?

- Can we identify packages with executables and those with libraries
  separately. Ones with a bin are easier to filter as rest require
  dependency analysis.

- Some autoremove tool (native if one is not using pkgin)

- I have looked at pkg_leaves which helps to some extent

Are there good tools / methods to overall manage pkg disk space better?

Mayuresh