[mythtv-users] Can apt-get upgrade break an install?

[David Lyons]

I went and did an apt-get update/upgrade to apply the latest packages to
my mythtv box. When the packages were installing I got a warning that my
/etc/apt/sources.list file was replaced.

When I looked at the above file I no longer had Axel Thimm's site listed
as a source (which I added back in).

That being said, as a newbie, should I be more careful about running the
above commands for fear that it may break something mythtv requires.

My myth box is my only Linux box running. I don't know enough about
Linux yet to be able to recover from a dependency problem that may break
my install. 

Currently its only function is for mythtv; which I love; and do not want
to break in any way. 

Thanks