How to clean up unnecessary dependencies?

[Simon Rönnqvist]

  Hi!

When installing packages in Kubuntu/Ubuntu or Debian the packages usually also 
want dependencies to be installed. When removing these packages again they 
don't seem to care about a bunch of dependencies being left installed. Is 
there a way to easily clean up unnecessary dependencies?

The best way so far that I've been thinking of is to use synaptic to install 
the software, because synaptic keeps track of installation history. Still 
this only gives a list of packages installed at a sertain occation, which 
means that one will still have to remove them manually one by one.

The ideal would be if the package managers would keep track of which packages 
were picked by the user and which were installed as dependencies. All 
packages just installed as dependencies should also be able to be removed 
automatically as soon as no 'picked package' or dependency of a 'picked 
package' would be dependent on it.

  cheers, Simon