Why turn off pitot tube heating? I'm merely an amateur simulator (X-Plane) pilot. On a flight yesterday the airspeed indicator stopped working. After the initial panic I remembered reading something about pitot tubes freezing, found the pitot heating switch, and turned it on. The problem was resolved immediately.

This led me to think: Is there a good reason to not turn pitot heating on before take-off, and leave it on for the entire flight?

I'm flying a Sud Aviation SE 210 Caravelle
I'm not sure what kind of airplane that you are flying in the simulator, but the checklists for jets typically do have you turn the pitot heat on just before takeoff and leave it on until after landing, just so that this is less likely to happen.



Update: I found a French checklist for the Caravelle and it says to turn on the pitot heat before takeoff:


  Rechauffage Pitot.....MARCHE