[Mrmerlin]

anti ice = used before entering icing conditions
deice = used after ice has accumulated usually done on the ground and on the leading edges of the pneumatic system

4 different types of systems

Bleed air used to heat the leading edges of the the wings and engine nacelles and horizontal stabilizer also used to heat the wheel brakes and windshield this is generally used in a turbine powered aircraft ,
some turbine aircraft also have inertia doors to reduce the chance of ice ingestion PT6

Electrically powered heated blankets used for leading edges and propeller roots, electrically powered pitot tubes, electrically powered heated windshields

Pneumatic systems used to fill rubber bladders that are glued to the leading edges they fill up like a balloon and crack off the ice, can be powered by a vacuum pump and or bleed air from a turbine

TKS systems a fine mesh screen placed on the leading edges of the wings and tail that bleed deicing fluid,
Also an alcohol system that may be installed to clear the windshield and radome.

As previously posted there is a big draw on elex power if the heaters are used
Also there is a reduction in power available if the bleed air system is employed, and or reduced climb power available.

So the anti ice systems are not in use unless visible moisture is seen and the OAT is 10 C degrees or less

Though on just about every aircraft the pitot heaters are turned on on takeoff, this may also include the angle of attack indicators and the static ports

NOTE for the the smaller single engine aircraft these are generally kept off till icing conditions are encountered and generally they only have pitot heat.
Plus usually driven off the exhaust manifold a windshield defrost and and carb heat