When someone stops using tobacco and nicotine products, it can take more than two weeks for the blood level of cotinine to drop to the level that a non-tobacco user would have and several weeks more for the urine level to decrease to a very low concentration.
Pre-school children require 10-13 hours a day. School-age children require 9-11 hours a day. Teenagers need about 8.5-9.5 hours on average. Most adults need 7 to 9 hours a night for the best amount of sleep, although some people may need as few as 6 hours or as many as 10 hours of sleep each day. Women in the first 3 months of pregnancy often need several more hours of sleep than usual.
Sleep has four stages, each stage lasts 90 minutes. Stage 3& 4 are the deep sleep cycle. To have a good sleep , you need 3-4 hours of deep sleep and the balance would be light sleep. If you wake up several times,that would interfere with sleep quality. Total sleep should be around 8 hours although it is dependent on the individual.