i have one of the new clear ones, they are like a solid mouthguard and they look invisible (unless there is condensation inside it)
I have to wear it 3 days constantly (except brushing and eating + hot drinks) and then each night till sept, then i get checked and go for 1-2 nights weekly apparently
luckily my orthodontist keeps up with technology, my brothers hurt like crazy and when he got to the weekly bit on of his teeth moved and he can't be bothered now
well, i hope i don't fall on it when i put it in a pocket on CCF Cadets camp next week!! because i go on holidays and won't be able to get a new one for 3 weeks!!