The B757 RB211 E4 is so over powered that a reduced thrust T/O is almost always used. As a result of this, every 3-4 weeks it is a requirement of most companies I have worked with, that a full power T/O is carried out to ensure full power is available in the event of an emergency.
The other time that a full power T/O is required is when a thrust reverser is locked out (I think this is the case on every a/c type).