It is always advisable for everyone (not only teenagers) to follow a certain routine of early to bed and early to rise. It helps in the proper functioning of the body and keeps you alert for the whole day. Yes, parents should expect their teen children to follow a routine of going to bed and waking up in the morning, but parents should not be strict enough in fulfilling their expectations. Some people tend to work and learn better at night. In that case, there should be enough freedom, so they make their decisions on their own. But, everything should be under control. Excess of anything is bad. So, late to bed and late to right notion should not always be allowed. It deteriorates the functioning of the body in the long run.