This hasn't been a particular issue so far, because where it did happen I played it safe and re-stripped the ends. But mainly to save effort in future (particularly where there isn't much spare left to re- strip), I'd like to be sure.
1. If, when stripping the inner insulation off twin and earth, you "nick" the core with the strippers slightly, is that likely to cause enough difference to the resistance of that core to make it unsafe?
2. Similarly, will overtightening terminals such that the wire is crushed be a problem, so long as it is not actually broken?
A test with a multimeter showed negligible/no change in resistance where I did this deliberately to a small length of test cable so I'm inclined to say "not a problem" - but am I right?