Depends on how much you value your comfort
Your house will always lose heat (assuming outside is cooler than inside)- how many watts per hour depends on structure, air movement, wall wetness and temperature gradient. The greater the difference between outside and inside temperature, the more watts per hour will be lost.
Your boiler will run more efficiently on one long burn (say 20 mins) than on 4 short burns. If the house warms up fairly quickly from ambient then on demand heating can work well.
There should be a dwell value on your thermostat so the boiler isn't clicking on and off every 5 minutes. If that value is adjustable, play with it so the 'satisfied' temperature doesn't feel uncomfortably hot and the 'call' value doesn't feel uncomfortably low.
Best value of all is insulation, thick curtains, draughtproofing, carpets, more clothes, blankets when you're sat watching the telly.