insomnia
"I've been on Lunesta now for approximately 8 years. I take the 3 mg does at this point and usually take it every other night. The few nights that I can't fall asleep within 30 minutes or so, I'll take 1 pill and normally I can fall asleep within the next half hour for about 6 hours. When I do fall asleep at bedtime without taking a Lunesta,  I'll usually wake up at 2 or 3 and can't fall back to sleep. Taking a Lunesta at that point will give me the additional 3-5 hours more of sleep.  
After taking it for so many years, I don't even notice any metallic taste . I usually do not wake up feeling groggy or tired.  Works great even though I'm concerned about long term unknown health issues. Don't want to grow two heads.."