Just adding a few points...
Most of these points can not really be checked by the insurance as long as your story is legit (e.g. I never drive my parents car, but officially I do once or twice a week...also my car is half the week at my girlfriend...but officially it is every night in my garage or the garage at work...)..
And because of that, many insurance companies do not change the insurance value, even if they ask for this detail ![]()
E.g. Admiral Direkt.
They ask for a parking garage, but it has no effect.