For a fire site to remain viable throughout the night, it has to burn long or hot prior to being left. So your fire the day/eveing before is paving the way by heating the ground around it so that the potential embers have very little work to do other than survive the night being protected by hot soil and ash around them. This brings its own risks of your fire spreading underground through peat or roots though!
You should, of course, have the kindling and fuel for the morning fire sorted out and ready to go, but there should also be an excess of fuel so that, should you wake during the night (bio breaks for instance), there is something to hand ready to put on the night fire and extend it's life.
At least if you have a fire planned for the following day, you only have its ignition to worry about in the morning.
ATB
Ogri the trog