Brushing your teeth, reading a book; most of us have things we do each night before we hit the sack. But some habits could actually be causing you to lose precious hours of sleep.

“They say I can’t sleep and I haven’t been able to sleep for a long time when you really sit down with them and go through their habits in detail you find a lot of people have very poor sleep hygiene but they don’t realize it,” says Dr. Holly Hannon, a sleep disorder specialist. Habits that contribute to poor sleep hygiene include working on your computer, talking on the telephone, or watching television close to bedtime or while in bed. Dr. Hannon says, “Something that may seem like a really small detail can make a big difference over a long period of time. It’s very difficult to sit down and look at all those things and try to change things that you have been doing for years and years.”

She says bad sleep hygiene can cause you to develop conditioned insomnia.

Writing a sleep diary can help you recognize the habits that you may want to change. “What time are they going to bed? What are they doing before bed? How long does it take them to get to sleep? How many times are they waking up? What time do they wake up on the morning? How do they feel throughout the day?”

It’s also important to set aside about an hour of relaxation time before bed so that your body can prepare itself for a good night’s sleep. Sleep specialists say drinking caffeine in the afternoon or evening can greatly affect your quality of sleep that night.