I have read about incorrect numbers being used when calculating reduced thrust that have resulted in close calls on takeoff, so being ready to push the levers forward if not happy with the takeoff performance is not a bad idea. I have had errors in loading (up to 20,000 pound in the 747 and 2000 Kg in a 748, which as everyone knows is an improvement on the 747) that would have been quite a problem if I had used reduced thrust at the time. I personally add .02 EPR to any reduced thrust calculation to cover instrument error!
Full thrust takeoffs and max power climbs, max cruise settings at the highest altitudes will save on fuel. With fuel costs so high, it might be necessary to scale back on reduced thrust takeoffs.
The reason for reduced thrust is to reduce engine wear, and the biggest cause of wear is temperature. The argument is that it is most important to keep the EGT/ITT as low as possible. But reduced thrust means that the takeoff rating has to be held for a longer period. Has a study been made to determine whether a single high temperature limit held for a short period does more damage than a lower number for a longer period of time? Maybe the only reduction that needs to be made is a small one, just to keep the temps away from peak, rather than the large reductions we use now, but have to hold for longer periods.
And that always gets me back to the argument about flap. Using Flap 10, say in a B744 instead of flap 20, gets the airplane off the ground and up to the point at which climb thrust can be set in a shorter time. This would lead to less engine wear, but most airlines will not even consider it.