will it last 5 years .... yup ....
will it last 10 years yup ....
will it last 255 years yup ....
by the time the CPU dies because of the tiny increase in voltage you have given it you will not be using it anymore. Its a simple fact that as long as you take even ok care of it the cpu will outlast its own usefullness. This is mostly of course since you will throw it out long before it dies. It will cost more in electric to run it then to buy a newer faster one. Take it from a long time overclocker. I have a pentium 2 celron 300a (remember these guys) @ 504 that ran 24 hrs a day 7 days a week for years crunching numbers for seti. I still own it ... its thrown in a cardboard box with moterboard still attached.
I have NEVER had a cpu fail from overclocking. I have had alot of OTHER components fail GPU, memory power supply hard drive butt load of fans etc ... but cpu forget about it.
-keep it clean
-keep it cool by not craming too much around it (if possible)
- thermal paste could use to be reaplied every once in a while thats about it.
if the CPU fails before anything else in your laptop be happy in 20 years it will cost a dollar to buy a used cpu replacement.
Currently my pentium m 2.0 is purring away at 2.66. message me in 10 years I will still have the same cpu in it. Probably will be sitting in a cardboard box next to my last notebook though.