Do PSU units wear out over time?

Everything wears out in time.  

For example, there's a lot of talk about "capacitor aging". I am ambivalent on the subject. Yes, capacitors do age. I am just uncertain about the practical effects. There's simply too much 20, 30, and even 40 year old commercial and military electronic equipment still running within spec today.

Buy good stuff, operate it within conservative limits, and don't worry.

I have a 7 year old 400 watt Antec still running. Now, admittedly, it has spent its life running at less than 50% load. But still, it's 7 years old.

I like Corsairs. I have 5 of them.  

As previous poster stated, Power Supplies do indeed wear out. That is a reason FOR getting a quality one, not a reason against. As for overkill on wattage, Power Supplies are typically most efficient at about 50% load; but the one you are looking at is 80 Plus Silver certified so it is rated to be 85% efficient at 20% and 100% loads and 88% efficient at 50% load so you won't lose too much efficiency by under-loading it. I am not going to say whether that particular unit is absolutely the best deal or not. However, I will say: Corsair is a good brand, 80 Plus is (imo) an absolute must, you should definitely get a good power supply, and don't forget to surge protect. The practical effects of not getting quality components and treating them right is that someday sooner than latter your power supply could fail, and I've seen and heard of some fairly spectacular failures - not a good thing to risk.

The main thing that will wear out in a PSU is capacitors. Usually good prand PSU's using good brand capacitors will unlikely wear out within 5 years. Some cheaper PSU's can have leaky capacitors within a year or two. Running a PSU near to its max output and heat will also shorten the life of it. Its also a good idea to clean out all the dust which will accumulate over time. To do this you need to take out the PSU, open it up (if not under warranty) and used compressed air to blow all the dust out of it. And yes, 850w corsair is a good choice, who cares about overkill. More is better than not enough.

I'd say they do wear out, but I'd also say that many of us here and on the intarweb won't really have a PSU long enough to see it wearing out.

I can't speak for every one, but at least for me, I go through computers every few years. From what I see here and elsewhere that is not an unusual trend.

Bottom line, like everything else in this world, it does wear out, but its lifetime will exceed its usefulness.

Okay gotcha - what would you guys do? Opt for the 650 corsair and upgrade again later in the future, or invest in the 850 now?

It'll probably be 3+ years before I get rid of the 460's.

Just to add, the Corsair unit you're looking at is a very high quality unit and comes with at least a five year warranty (check the website for details on exactly how long for your country). If it were me, I'd rather get the larger PSU now than have to upgrade again soon. That being said, the current trend towards energy efficiency etc. means that general power consumption is on the decrease.

Fan bearing wears out

Connectors corrode eventually. It varies on the type of plating use on the power connector (gold, nickel-plated...etc)

Capacitor Age
Below is the path for PSU capacity calculator. At the bottom is capacitor aging with footnote #4.

My PC's are always on. It is because I run jobs that run for days or weeks. Alternatively, I have applications that run 24x7. With that in mind, I factor capacitor aging and oversize my PSU base on my calculated load. I am one of those who spent money on PSU and it saves me a lot of headache
http://www.antec.outervision.com/

- Fan bearings do wear out, but if its good quality and kept clean they last 10+ years.
- Ive never seen PSU connectors corrode unless they have been left outside...
- if you leave the computer on all the time the capacitors will not last as long, so dont do this unless you have to.
- heat is also a factor.
- quality varies between capacitors, they can last 1 year or 15 years so capacitor aging can not be calculated based on the "Average" capacitor.

another factor in psu aging is how clean your power is. in florida we have alot of storms and alot of power outages, so i replace my power supply every 3 years, i also keep it plugged into a good UPS to protect it, also replace this every year .. which is probably overkill to do both but hey i need my stuff to last a long time and my tv is also plugged into the UPS