Taught me always add 5kt for the turns in the circuit and watch the air speed.
As long as you are aware of your speed there is no need to add anything more than the correct speed.
Better check the C172 Flight Manual, don't think intentional spinning or spin entries are approved with flap extended.
it is not really a spin entry as such - but you should not be using rudder in the recovery just centralise the controls and it will recover.