Fire spreads in minutes but smoke kills in seconds. Most fires occur between 10pm and 4am, smoke will not wake you if you are sleeping when a fire breaks out in your home.
A working smoke alarm can wake you but you will only have minutes to escape and it will be more difficult at night when people are asleep and it is dark. Escaping is a lot easier if you have planned an escape route and everyone knows where to go and what to do. It is best to know a least two routes out of your house, to keep these clear and free from obstruction, if locked keep the keys close enough to reach them in an emergency and close doors at night to protect your escape route.