So you know how the other half lives, I clean my machines once a year. Usually during the FB downtime in December. Maybe I'm just lucky, but I've never lost anything but 1 PSU and it died quietly and it was a piece of crap I bought cheap and it still lasted 4 years. I pay little attention to temps except when I initially build a system. After it has proven worthy I don't really look at it until it starts erroring out wus. That goes for cpu and gpu. I'm of the group (probably a minority) that feels if it's working, don't muck around with it. Not everyone can do that, but I'm mostly lazy and don't want to create work for myself. Maybe that's puts me in the stupidity class, but it's served me well up till this point.
I will say, when I hear about all the work others are doing I feel sort of guilty and think "maybe I should do that" and then I think better of it and go have a beer.