I used Ubuntu 14.04 (Trusty Tahr) for about a year (actually upgraded it from Ubuntu 12.04 (Precise Pangolin)), and during the time I installed some packages, and removed some other packages.
Now I think it's probably time to clean up the system as it's likely several unused stuff is lying out there (both from the old 12.04 and the new 14.04), and I hope to have a cleaner system that works faster.
I found these two links:
Both links seem good, but when I came across to what they said about
Bleachbit then one says yes, and one says no - a bit contradicting.
What should be done for this common task?