Warming up engine

My co-workers keep telling me that I do not have to warm up the engine of my vehicle. They say that newer vehicles need not to be warmed up anymore. But my response is, if the vehicle have an oil heater it is possible. But if none, it needs to be warmed up especially during winter time. I live here in Canada and the temperature is really freezing during winter. Thank you very much and hoping for your most appreciated reply.