Adding specific repos for an application
 

Hi

I've learnt to be a bit more careful now, after messing up my install by recklessly adding sources.

However, I have added a few (mainly for specific apps, always by following some guide).

Now - best practice - Should I comment out the new source once installation is completed, or should I leave it in there?

Just for reference my sources.list looks like this at the moment:

all of those specific repos have an impact onmore than just one aplication.
basically, apt-get gets different versions to choose from now, and iirc it will default to the highest version, which might cause breakage now or later.
otoh, if you disable these sources now, you won't get updates for those specific apps.

all this can be fine-tuned ad infinitum! basically you did nothing wrong by adding wheezy-secific specialized repos.
i'm skeptic with linux mint repo there, are you sure it was good advice to add it?
why do people always need the newest of newest browser versions, there's nothing wrong with iceweasel!

Thank you.

The Mint repo was added purely for Firefox, and it was just a guide I followed.

Iceweasel doesnt support FF Sync which is a feature I use/rely on :)

You're using Debian Wheezy, the guide you're referring to is likely referring to LMDE, which is based on Debian Jessie. There may be incompatibilities in the future, alas if you comment out the repo, you won't get security updates. I suggest you just continue to use Iceweasel.