What does full reverse do on a dry runway?
Reduce brake temp by using reverse deceleration effect to decrease applied automatic braking to a achieve the preset deceleration rate.
Only at and below ab 2 do you gain landing distance from applying full reverse,have a look at your qrh.
But full reverse also:
Increases noise at airport
Decrease engine life, higher engine temp,
Increase fuel burn
Increases airframe vibration
Scares the **** out of some passengers including kids and new flyers.
Unless you need full reverse dont use it,brakes are to cheaper to change than all of the above effects.
Calculate your landing distance and then decide on which a/b to apply.
Reverse is necessary for wet and contaminated runway or if runway limited/own performance limit.
Using full manual braking is just plain irresponsible if not required for emergency purposes.