Hi guys. For a good quality PSU, is there a good "rule of thumb" to go by as to the usable life span? I ask only because I am on the home stretch of building my 1155 system, and I currently have a Cooler Master GX 650W psu that's getting to be about 3 years old. It's been powerering the system in my sig since purchased new. On average, I'd say my computer is on about 50 hours a week, with 50% of those hours used for 3D gaming. The rest of the time it is either powered off or in Sleep Mode. Should I consider a new PSU, or should the GX 650 keep chugging along for quite some time yet?