As long as the target is reasonable.
A cpu that'll last you, say 12 years, will bite the bullet at 11 with a mild OC.
Do an extreme one, and well... no telling with that one. Could be 6 years, 3 months, or 3 days from now - depends on how far you push it within reason.
If you implement speedstep and adaptive voltage, the processor will slow down and reduce voltage when there is little to do.
That is a good thing.
Look at cpu-Z, if you see the multiplier and voltage lower with little load, you are doing good
It doesn't matter, so long as you keep your temps below TJ Max there is nothing to worry about. Also as gefelt said speedstep is your friend, as it will reduce Mhz and voltage when your not doing much.