I set the fire for a slow burn as I settle in for the night and place a couple if logs where I can reach them from the bed, to place on if I wake up cold.
Usually I have a couple of smouldering dog ends that I can relight with the bellows in the morning. At worst a few sparks from the flint and steel will start the process again.
Some people prefer to let the fire burn down before they sleep but I've never had a problem.