If not then please get some asap.
My dh is a firefighter and he has been out yet again in the middle of the night to a house which was on fire and they did not have smoke detectors fitted!! Luckily for them someone was on their way home from the pub (at 3.30am?) and spotted the smoke and flames and alerted the couple who were fast asleep in bed although the fire was in the roof just above their bedroom. If this bloke had not seen this they could have died.
Luckily most of the fires they go to, they do have detectors fitted and they all get out ok, but there are still a lot of people who have not (or they do not have batteries in them).
PLEASE, PLEASE make sure you have them and they work.