Proper start proceedures are also very important to protect engines. Engines don't last if you continualy do hot starts and they don't last if you don't let them idle for a while to cool down. Back when I still worked in cold climates, we use to use a pre heater to warm the engine before we started it. Once it was started we would idle it a bit above normal idle speed just to get things warmed up. Most of the time the Spey wouldn't idle at it's normal idle speed unless it was warm any way. Not as much of a problem on JT8D or the Lycoming on the BAE146.