^Bleeding as per Toyota is to be done at every brake oil/discs change which is 40k kms.
At times even when discs are faced, the desi mechanics fiddle with the brake fluid, air comes in the system which acts for delay in braking.
Bleeding is done by pumping the pedal lightly and then hardly(in local words - brake banai jati hai); the air in the system escapesd when one of the outlet for fluid from a wheel is detached in the meanwhile. The same process follows for the other wheel.
If it isnt properly done, one will notice a lose or not so perfect emergency brake specially.