For my personal laptop or even work station I don't see a reason to require the root password to install or update programs from trusted sources (i.e. repos from which we imported the gpg keys). In order to allow the regular user to perform such actions we use PolicyKit. As such we need to write 2 new pkla (PolicyKit Local Authority) files:
and copy/paste the following:
[Let All Install Packages] Identity=unix-user:* Action=org.freedesktop.packagekit.package-install ResultAny=no ResultInactive=no ResultActive=yes
This will allow all users to install new programs either by using pkcon or its graphical counterpart gpk-application.
In order to update packages we need to write a new pkla:
[Let All Update Packages] Identity=unix-user:* Action=org.freedesktop.packagekit.system-update ResultAny=no ResultInactive=no ResultActive=yes
That's about it. Now you can use pkcon install blah or pkcon update as a normal user. Alternatively you can use "System > Administration > Add/Remove software" or "System > Administration > Software update".