Your system will be in a perfect state once (maybe twice) in its lifetime.
The first time that it's perfect, unsullied, and unsoiled, is when it's installed (providing that you've ticked the box to update the packages during installation). Your system will never again be in such a pristine condition, because it has not had dirty human hands meddling with its innards.
The second time it's perfect is when it's turned off for the last time, with a job well done, and with a visit to the scrap factory well earned (or, in the case of cloud computing, a quick ethereal jaunt to silicon heaven).
In this section, you'll learn about different sources of packages, how to go about finding and installing new software, and the importance of keeping your systems secure and up to date (lest you end up as a headline on The Register).
It's not the...