Verified answer

"Have a good night's sleep". If you do not use the genitive case ("night's"), then your sentence is simply wrong, although I grant you that if the speaker is sleepy or a little drunk, it may be hard to hear the difference: one needs to be awake, and sober, to keep the two S's apart!.

I was having alot of anxiety before sleeping and could not fall asleep. Had many many sleepless nights.

I was just playing with the program one afternoon and wanted to listen to the �Power Nap� track. Next thing I knew I was waking up! Fell right asleep without trying. After using the �Fall Asleep� track, I could fall asleep right away. But I didn't realize that I shouldn't be using that one all night. Switched to Whole Night and have been using it ever since.

I can go to sleep with ease now. I just lay and listen to the sounds and next thing I know I am waking up from a nice sleep. I don't suffer from lack of sleep anymore. I keep an IPod with earbuds next to my bed and take it ALWAYS when traveling. The earbuds help block out ambient noise and the sleep tracks keep me sleeping sound :)

Reboot your brain & sleep soundly again?

It should be "Have a good night's sleep", but it's a very minor error that many English speakers will mix up. It's similar to "a day's work" or "an afternoon's rest". It's just one of those things you have to remember :) Hope I helped!

Properly, it's "good night's sleep", but since it's usually said aloud, rather than written, it sounds like "night sleep". The s's merge.

So, formal writing "night's"; informal, doesn't matter.

Grammatically correct it would be ''Have a good night's sleep'' or if you want to sound less formal you can just say ''Sleep well'' or ''Sweet dreams'' :)

Sleep Grammar