Should you use leaks or not?

The right answer is no, however you have the power to choose yes or no.

Mass majority of addons of mine are leaked uses, none bought. The collection I have (close to 1k addons), are partly checked (if i use one i check them out firstly).

Some leaks will have backdoors which can be used to abuse server at any given time (or until removal, etc..).

Big name addons like VCMod, etc.. should be bought though, or any other high quality addons that are actually worth buying.