Hello mga paps

how often do we change the thermostat of the cooling system (i.e. months, years or mileage reading)?

have installed one 82C MD997606 for a mitsubishi 4d56turbo. so far no overcooling on highways and overheating on traffic. operating temperatures is within the first and second line of the stock electric temp gage while 180 (82C) to just a bit higher than 200 F (93C) on the mechanical gage.
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TIA