It varies. I literally cannot get any sleep without Seroquel. When in a mixed state or manic, I'll get maybe 4-5 hours if I am still taking my Seroquel consistently, but that's with very broken sleep. Stress makes it the worst. When I'm doing a little bit better than that, it's usually anywhere between 5.5 hours- 9 hours. I know that's a really wide range. 7 hours is about average for me, but I can usually sleep 8-8.5 if I don't have work the next day. 8 hours is healthiest for me, and I've been trying to do better with turning electronics off by a certain time, and making more than an effort as much as possible.