In the 20 years I've been in business, I've personally built around 150 computers, from absolute base spec to high end "Gaming Rigs," built to my customers requirements. They knew before any build exactly what they were going to get!
In the first years I used "PCChips" motherboards, Graphics cards etc, $10 PSU's (from the "Happy Sunshine Apple Blossom Company of Taiwan!), the cheapest ram I could find and Maxtor HDD's etc in the low priced units.
Mid to high end got Alwill, DFI, Abit, Soltek, MSI and a few other mobo's. I used $30-$50 PSU's and Corsair or Kingston Ram.
None of my customers ever overclocked, or were even interested in overclocking their computer!
I always tried to inform the client on the value of a "high end" PSU, especially for a gaming box.
Now I build only with ASUS or Gigabyte boards, (ASUS only in gaming rigs), ASUS or Gigabyte VDC's, Kingston or Transcend SSD,s Corsair or Kingston Ram and $80 PSU's! People will not pay for good PSU's no matter what you say!
Long story short, in that time I can honestly say that I have had one PCChips motherboard replacement, (after about 3 years trouble free!)
maybe a couple of VDC's, again after fairly reasonable service life, and the main one: only about 5 "el cheapo" PSU's, but still well after the warranty had expired! I've never replaced a PSU in a gaming box that I built!
I have, however, replaced a "high end" EVGA PSU for a client that had his computer built elsewhere.
I've never had to replace any component during the warranty period, apart from a failed OCZ SSD in a (mid range) game machine this week!
I've even traded some of my builds in after 3~5 years of trouble free (hardware side) computing and resold them to others that in many cases are still using them, even though some of them are up to 10 years old!
This is my own personal experience and I know that there are many horror stories out there. I've just been lucky I guess!
I am an avid "gamer" myself and my "gaming rig" is about 6 years old with a $70 "Penguin" 650 watt PSU!
If your interested in the other specs they are: AMD X6 1090T, 16GB "off the shelf" Corsair Ram, S/H Gigabyte 750Ti (from a trade in 2 years ago), 2TB WD "Red" (also about 2 years old from a trade in) and a Gigabyte Mobo, (forgot which one now!) Works fine for me!
Plays any game I throw at it includeing the new DOOM with settings on medium to high.
Never once given me trouble! (Apart from once overheating due to the stock CPU cooler being clogged with dust)