Everyday life involved using fire much more than most of us do now. Fire was used for heating, lighting and cooking. It took time to light a fire, and with several fireplaces in many households, it was common not to put all fires out when you went to bed at night.
There was also the issue of how to get rid of the ashes of a fire. This was what had started the London Bridge fire of 1633. A servant had left a tub of ashes under the stairs, not realising that some of the ash was still hot. 42 houses on the bridge burned down as a result.