1 hour isn't enough, the entire point of using extensive stability testing is to remove any doubt that it's your hardware.
If you don't, how do you know it is your overclock, or a software problem? How do you know that your computer isn't crashing but is in fact causing data corruption that you won't pick up immediately but years into the future to find your photos of your kids graduation are corrupted.
There can be very good reasons to doing proper stability testing if you're overclocking, you want to push your hardware as hard as possible to remove any chance of that happening, especially when you bear in mind that cooling and PSUs etc age and deteriorate.