no way, they told you about 12 hrs just to sell it!
it will be damaging, really, because they're not professional lenses, like acuvue etc, so please wear them 6h a day max
every person has individual eyesight and eye problems of course, sometimes relatives tend to lend their glasses to each other because one has them prescribed and another one feels like they 'work perfectly' even though he haven't checked his eyes properly. which is absolutely wrong and damaging too. that is why trying other people's glasses can hurt for you
I've been having eye probs since I was 10, and since then I managed to cure my 1 eye completely without any surgery involved. that's why I'm so careful about my eyes & care & lenses