If your system is running, you don't need a new PSU, there are video cards out there that experience coil whine (google it) and the higher end AMDs are known to do this from time to time, Here's the thing though, a cheap PSU provides power that spikes and puts unnecessary load on your components, also, it might not, the best power supplies provide clean stable power for all components, this in turn increases your longevity. Here's the hard part, no one can tell you when your computer will die, some people run hot with crap components and their systems run for a decade, or you could get a DOA from a top tier piece. I love my computer, it's not the fastest, but I use it for everything, gaming, talking on the phone, EMail, TV, I use it all the time, so I want to play where the numbers favor me. I don't have the best CPU or Video Cards, Memory, it's good, but it's not the best, but I have a tier 1 PSU. Always have, Always will. It's the one part I won't settle for less on, and in my 20 years building computers, I've only seen one PSU fail, and that was three builds after it's initial purchase.