You have many answers here, most good, a couple bad. If you want your CPU/motherboard to last 8 years you need to make sure you are safe both with heat and voltage.
I am using a 4 1/2 year old [as of this writing] i5 3570K and run it at 4.0 GHz 24/7, and occasionally bump it up to 4.4 GHz for video editing. When my CPU was new 1.095 volts is all I needed for playing games stable.
Now that it is 4 1/2 years old I have bumped that up to 1.105 volts to run Microsoft Flight Simulator with add-ons and flying the Carenado B200 KING AIR HD SERIES [aircraft]. That may seem odd, however, that combination is VERY hard on CPUs. When the Microsoft team designed FSX they envisioned Intel shoving CPUs to 10 GHz to run the game/simulator smoothly, of course that never happened, and some add-ons make FSX even more demanding - and people think Crysis was hard on computers.
Also, when using MS-FSX my temps hang around 58 degrees [maximum] for core 0 and the rest of the cores are much cooler. At 4.4GHz core 0 [the hottest core] runs around 63 degrees and the rest run from 54 to 58 degrees C. I have found that I do not need to run 4.4GHz on any game, including FSX with demanding add-ons. I am using a Noctua NH-C14 140mm x 2 SSO CPU Cooler, I think they are no longer produced, it is still a good air cooler.
High quality lowest latency and lowest voltage RAM makes a difference with games that use a LOT of CPU power [HQ RAM will let you overclock higher because it will not give you problems. If you crank up the CPU frequency and wonder why CPU demanding games are crashing, show odd things on your screen, and so on, that can be caused by either bad RAM or RAM that is pushed too far [it may need to have extra voltage to run demanding games]. Many people overlook RAM, however, the CPU talks to your GPU by using your main board RAM [local RAM], and the slower your RAM moves data the slower your games will run - period.
Just a thought, I have had my CPU to 4.8GHz, however, I do not like running any speed over 1.280 volts - I want this rig to last another 4 1/2 years. [And, as slow as Intel is it will probably be another 4 1/2 years {8 years total} before a CPU from them is 50% faster than mine clock for clock ....]
If you want to keep your CPU and motherboard running for a long time, keep the volts and temps low.
NOTE: Edited for 2 spelling errors.